Dynamic method and device for inspecting thermal-physical properties of fluids

FIELD: test equipment.

SUBSTANCE: metal probe of vibration viscosimeter is disposed inside metal dish in tested fluid to make it thermally isolated from outer space. Viscosimeter is excited with preset frequency and with preset force. Temperature of the dish is changed monotonously and continuously to follow specified rule at speed to exceed speed of establishing processes of change in temperature of tested liquid inside the dish. Temperature of the probe is measured within whole preset range of changes in temperature of the dish as well as amplitude and/or phase and/or frequency of oscillations of the probe. Density, viscosity, thermal conductivity, heat capacity and thermal diffusivity of tested fluid are measured depending on fluid's temperature from the relation of heat diffusivity of fluid and from the relation of viscosimeter's probe forced oscillations. The main feature of the device realizing the method has to be the metal probe of viscosimeter made in form of copper ball or silver ball disposed in fluid for thermal insulation onto rod made of thermo-insulating material. Measuring converter of probe's temperature is made in form of thermocouple and built inside probe. Second measuring converter of probe's temperature, also made in form of thermocouple, is placed onto bottom of metal dish thermally insulated from environment.

EFFECT: improved efficiency of test.

10 cl, 5 dwg

 

The invention relates to the field of study of the properties of liquids using heat tools.

Known vibration methods for determining the viscosity and the associated parameters of the liquid. For example, in [1] described a technique in which the probe plate type immersed in the test fluid and act on it with a given excitation power at the frequency corresponding to the resonant frequency of the system. After establishing the amplitude of forced oscillations of the probe measure the amplitude, then taking into account the amplitude, the frequency of the driving force and the square of the probe calculate the viscosity of a liquid.

The method of determining viscosity is characterized by the following disadvantages: the use of a probe plate type complicates the solution of equations in cases where the results of calculations required to determine the viscosity and the density of the liquid; the relatively large dimensions of vibroisolation and other devices required to implement the above methods do not allow to create a portable measuring devices.

There is a method of determining the specific heat of liquids by direct heating in the adiabatic calorimeter [2]. Before the experiment in the calorimeter fill in the reference liquid of known specific heat, and calculate the heat capacity of the calorimeter. Then research what has been created, the liquid is poured into insulated from the external environment calorimeter, equipped with a heater for heating the liquid, a stirrer and a thermometer. Over time, the duration of which is measured, is the heating fluid through the heater. Measure the power delivered to the heater. In the process of heating the mixed liquid. Measure the liquid temperature at the beginning and at the end of the heating process and calculate the specific heat of the liquid under study.

This method has the following disadvantages: quite a large amount of a measured sample; a sufficiently large measurement time, especially if you want to explore the dependence of heat capacity on temperature in a wide temperature range; the inability or increased difficulty in implementing this method in a portable device.

For determining thermal conductivity and thermal diffusivity of liquids used method regular heat mode [3]. In this case, as a rule, used such methods of measurement where the regular heat mode of the first kind.

Closest to the invention is a method of determination of thermal conductivity of fluids with different types of biocalorimetry [2]. When implementing this method, the analyzed liquid is poured into biocalorimetry, basic elements of which are the case and the core, carried out the copper and separated by a thin layer of the liquid under study. To the core of the calorimeter pressed hot junction of thermocouple and the cold junction of thermocouple is immersed in the same thermostat, which is immersed in the body of biocalorimetry when conducting the measurements. Directly before measurements biocalorimetry heated to a predetermined temperature in a different thermostat, and then transferred to thermostat, in which is immersed the cold junction of thermocouple. After the establishment of regular thermal regime in the liquid, the measured values of thermo-EMF of a thermocouple to determine the change in time core temperature and body biocalorimetry and calculate the cooling rate of the calorimeter, and then given the known parameters of biocalorimetry calculated thermal conductivity of the investigated liquid.

In this case, first, determine the conductivity of the liquid, and then involving other known parameters of the liquid is calculated from the coefficient of thermal diffusivity. The disadvantage of methods based on the implementation in the course of regular measurements of thermal conditions of the first kind, is the difficulty or even impossibility of correct calculations in the case where, in the course of the same dimensions, the task of determining a number of unknown thermophysical properties of fluids, including heat. In addition, these methods are very labor is capacity in the study of the dependence of thermophysical parameters of temperature.

Describing the above-described methods in General, it should be noted that all these methods are oriented to produce the definition of any one of thermophysical parameter of the fluid at a given temperature or within a narrow temperature range and, in the best case, the results of the determination of this parameter to calculate associated with any other parameters, such calculations typically require knowledge of the values of any parameters of the liquid, which must either be known in advance, or should be measured in other ways. It makes difficult or impossible the implementation of many measurements of thermophysical parameters in a single process.

The known devices for the study of thermophysical properties of liquids or do not allow the inventive method, or do not allow to fully exploit the advantages of the proposed method.

The known device [1] to determine the viscosity of liquids using vibroisolation. Their disadvantages: no possibility to measure the temperature of the investigated liquid directly at the point of location of the probe vibratissime, which introduces additional errors in the case study of the viscosity on temperature; the described device the VA are mainly designed for use in stationary conditions.

Described in [2] the device for determining the specific heat of a liquid by the method of direct heating in the adiabatic calorimeter also has several disadvantages, in particular, the device without the addition of its special cooling devices sample does not allow to make measurements at temperatures below the ambient temperature.

Know the definition of thermal conductivity of liquids using biocalorimetry [2] and [3], which are also characterized by a number of disadvantages, in particular, significant difficulties in miniaturization of such devices, a very complicated geometry of the fill fluid volume, which makes it difficult to rinse biocalorimetry when changing samples.

All the above devices are also common shortcomings, in particular, the difficulty of automation of the measurement process and cannot be determined in a single process several parameters of the investigated liquid. All this forces the user to create a new device for implementing the inventive method.

The prototype of the proposed device is an analyzer low-temperature properties of multicomponent fluids, implemented in accordance with the patent [4].

The known device includes a housing, which has United with DC sources two thermoselect the practical module with thermo-accumulating bases element between them; the first of the modules is connected to an adjustable current source and has thermal contact with the cell cavity for placement of an investigational multicomponent fluid, which placed the measuring transducer and temperature sensor temperature dependent physical parameter, the outputs of which are connected to the input of the register, the output of which is connected to the input of the control device of an adjustable current source, while the second thermoelectric module is provided by means of the heat sink, for example, an air fan. In the device the sensor is temperature-dependent physical setting is made in the form of fiber-optic sensor optical transmittance of the investigated liquid.

The disadvantage of this device is that the device measures only the temperature opacities and crystallization, indirectly indicating a change in viscosity, and does not allow quantitative determination of the viscosity of the liquid, to investigate the dependence of viscosity on temperature and does not allow you to explore other thermophysical parameters.

An object of the invention is the simultaneous study of the dependence on temperature: viscosity, density, thermal diffusivity of the fluid, as well as its thermal conductivity and heat capacity.

To solve this problem mobile is a dynamic way to study thermophysical properties of liquids, at which sequentially according to the time change and measure the temperature of the investigated liquid in the cell and record the temperature dependent physical parameters of the liquid, characterized in that the metal inside the cell in the investigated liquid post heat-insulated from the external environment of the metal probe vibratissime excited at a given frequency and with a given driving force, uniformly and continuously over time at a known law of change of the temperature of the cell at a rate greater than the rate setting process temperature changes of the investigated liquid in the cuvette, measure the temperature of the probe throughout a given range of temperature change of the cell as well as the amplitude and/or phase and/or frequency oscillations of the probe and determine the density, viscosity and thermal diffusivity of fluid, depending on its temperature according to the equation of thermal conductivity of the liquid and the equation of forced oscillations of the probe vibratissime.

In accordance with the method, the temperature of the cell change by applying to it a known constant or monotonically and continuously time-varying heat flux and further define the heat capacity and thermal conductivity of the investigated liquid depending on the temperature of the heat balance equation of the liquid.

TableAdapters for the study of thermophysical properties of liquids, including the case, which has United with DC sources two thermoelectric module with thermo-accumulating bases between them, the first of which is connected to an adjustable current source and has thermal contact with the cuvette to accommodate the investigated liquid, the liquid is placed measuring transducer and temperature sensor temperature dependent physical parameter of the fluid, the outputs of which are connected to the input of device registration and management, the output of which is connected with the control input of the controlled current source, the second thermoelectric module is provided by means of the heat sink, characterized in that the sensor is temperature dependent. the physical setting is made in the form of a metallic probe vibratissime placed in a liquid with the possibility of insulation from the external environment, the transmitter temperature probe integrated in the probe, and the metal cuvette termizolovana from the external environment and is further provided with a second measuring temperature Converter.

The transmitter temperature probe-type thermocouple measuring junction which is placed in the probe and the reference junction is cooled housing vibratissime.

The second measuring transducer temperaturregulere made in the form of thermocouples, the measuring junction which is placed in the bottom of the cell and the reference junction temperature-controlled.

Between the first thermoelectric module and the cuvette is placed with providing thermal contact between the heat flow sensor, the output of which is connected to the input of device registration and management.

Probe vibratissime made in the form of a ball of copper or silver having a protective film coating.

The rod probe viscometer made in the form of a capillary tube of insulating material, such as glass or ceramics, which are inside the capillary conductors of thermocouple.

Vibratissime cuvette and placed in the device can move relative to each other.

The invention is illustrated by drawings. The figure 1 shows the diagram of the inventive device, figure 2 shows the same circuit with a heat flow sensor. The figure 3 shows as an example the scheme of vibratissime. The figure 4 shows a diagram illustrating thermal processes in thermodynamic system "cuvette-liquid-probe. The figure 5 presents the equivalent of a physical model of a thermodynamic system.

In the housing 1 of the device for the study of thermophysical properties of liquids (figure 1) has two thermoelectric module 2 and 3 with thermo-accumulating bases element 4 between them, for example, from aluminum. The modules are at the core the ve of the Peltier element and is connected to the DC power source, when the module 2 is connected to the constant current source 5, adjustable in sign and magnitude, and module 3 is connected to the unregulated current source 6. For cooling the hot junctions of module 3 in the device used forced air cooling with fan 7. Cuvette 8 with the investigated liquid 9 is placed with the possibility of thermal contact on the module 2. The cuvette is made of metal with high thermal diffusivity, such as copper or silver. In the bottom of the cuvette placed the measuring junction 10 temperature measuring transducer of the cell (thermocouple) - this location ensures its safety when changing fluid sample and cleaning of the cell and the reference junction 11 is placed in thermostat 12. Probe vibratissime 13 made in the form of a spherical ball 14 of copper or silver. The ball has a protective film coating for the purposes of safety from chemical attack by the liquid environment. The measuring junction 15 of the measuring transducer temperature probe (thermocouple) is built into the bulb 14 and the reference junction 16 is cooled housing 17 vibratissime. The probe 14 have on the symmetry axis of the cell, which allows to simplify the formulas. Vibratissime 13 and cuvette 8 is placed in the device can move relative to each other for the purpose of cleaning the cuvette and replace the sample LM the bone. The stem 18 of the probe 14 is in the form of a capillary tube of insulating material. This is necessary in order to provide the possibility of achieving low temperatures of the liquid and to prevent uncontrolled heat flow from the environment into the liquid. Vibratissime has a sensor 19 of the rod position (probe), the output of which, as well as the outputs of the transducers 10, 15 connected to the input of device registration and management 20, is made on the basis of the microcontroller.

The figure 2 presents the same scheme of the device for the study of thermophysical properties of liquids, which shows a possible application of the heat flow sensor 21, which is posted with providing thermal contact between the cuvette 8 and the first thermoelectric module 2. The output of the sensor 21 is connected to the input device registration and management.

One of the possible schemes of vibratissime presented on figure 3. Vibratissime consists of a metal inner casing 17 in which are mounted the excitation device 22 of the oscillating system and the sensor 19 of the regulations of the oscillating system. Anchor oscillatory system is connected to the capillary tube 18, for example, of glass or ceramics, which serves as the conductor of the mechanical impact from the anchor to the probe 14, immersed in the test fluid 9 and strictly for replyname on the end of a specified capillary. Metal conductors 23 of thermocouple embedded in the bead-probe 14, passed through the capillary and moved outside of the vibrating system. Vibratissime has a system of internal temperature of the housing 17, which allows to maintain constant temperature of the elements of the oscillating system, regardless of the ambient temperature and the temperature of the liquid under study. Controlled items vibratissime surrounded by insulation 24, which also provides vibration isolation and damping of vibrations of the inner housing vibratissime. Surrounded by a heat insulation layer 24 of the inner housing 17 vibratissime enclosed in an outer casing (not shown). The outer body fixed to the positioning device (not shown)that provide temporary placement of the ball probe at the specified location within the cell. The electronic unit 25 vibratissime provides the excitation system at its resonance frequency, and sets the amplitude of the driving force. It is also possible to set the amplitude of the driving force does not depend on the oscillation amplitude of the probe vibratissime.

The inventive method is carried out as follows.

For the study of thermophysical properties of liquid microdose (of 0.15...0.2 ml) investigated liquid p is meshaetsia in a metal cell 8. Then, the liquid falls probe 14 vibratissime.

Before proceeding to set the required initial temperature of the investigated liquid, the probe and the cell by regulating the current of the current source 5. When the sensor module 2 current of a certain polarity cuvette can be heated up or cooled down. The heating rate or cooling is set by the device registration and management 20.

After you set the initial temperature through the device registration and management 20 carry out the temperature change of the investigated liquid from the initial installed with thermoelectric module 2. The temperature must either monotonically and continuously without jumps to increase or decrease. In this case, the heat equation allows for a fairly simple solution. The temperature difference between the cell and the probe can be determined from the equation of thermal conductivity of liquid thermal diffusivity. At a constant temperature cuvette temperature difference is equal to zero and thermal diffusivity of the fluid in the static mode cannot be determined. The rate of change of temperature of the cell is chosen such that the difference of the temperature probe and the cell was measured with sufficient accuracy. Measurements and calculations of compliance with these conditions are greatly simplified when choosing the material of the cell material is material with high thermal conductivity, for example, from metal. Continuity, monotonicity and the set speed of lowering of the temperature is provided by the device registration and management 20, and is defined functionally, mathematically. In the process of changing temperature simultaneously removed the dependence on time of the fluid temperature at the measuring junction of thermocouple probe and the cell. Also measure the oscillation amplitude of the probe, the frequency, the phase shift between the oscillations of the probe and the fluctuations in the driving force. Additionally, if necessary, measure the heat flux selected thermoelectric module from the cell.

Shown above control functions are performed through the device registration and management 20. As the control device may, for example, be used in the system presented on figure 1.7 (p.21) in [5]. You can also use the system described in str-282 (RIS) in [6].

According to the results of measurements of these parameters, calculate the following parameters characterizing thermal properties of the fluid dynamic viscosity fluid ηthe water density ρ, thermal diffusivity of the fluid and the dependence of these parameters on temperature.

Additionally, it defines the pour point of the liquid Tget theby analyzing the dependence of viscosity on temperature, using that f is t, when the solidification liquid is a sharp increase in its viscosity.

The measurement of the temperature difference between the probe and the walls of the cell allows to determine thermal diffusivity of liquids andWto explore the dependence of diffusivity on temperature. The opportunity is available due to the fact that the cooling of the cell is below that virtually eliminates convection and small (unit... tens of microns), the oscillation amplitude of the probe allows to neglect the effect of mixing fluid oscillating probe.

To enable measurement of heat capacity withWfluid between the cuvette and the first thermoelectric module is a heat flow sensor 21. In the simplest case, this sensor is a plane-parallel plate made of a material with known thermal conductivity λ, one side of which is in thermal contact with the bottom surface of the cuvette, and the other side is in thermal contact with the surface of the cold junctions of thermoelectric module 2. On opposite sides of the plane-parallel plates are "hot" and "cold" junctions of thermocouples (not shown). Thus, an electromotive force (EMF) of these thermocouples will be proportional to the temperature difference between the surfaces of the plane-parallel plate. By know thermo-electromotive thermocouple calculate the temperature difference between the surfaces of the plane-parallel plate. Further, given the known geometry of the plate and taking into account the coefficient of thermal conductivity λ plate material calculated heat flux W(t)selected thermoelectric module from the cell.

Information about the heat flux allows to determine the heat capacity of liquids withWto explore the dependence of heat capacity on temperature. Taking into account thermal diffusivity of liquids andWinformation about the heat capacity of the liquid allows to calculate its thermal conductivity λW.

Explain the physical and mathematical principles underlying the inventive method.

The equation of forced oscillations of small amplitude for the mechanical oscillating system with one degree of freedom has the form [7]:

where M is the reduced mass of the vibrating system,

r and mechanical impedance of the vibrating system,

In - the stiffness of the vibrating system,

x is the deviation of the oscillating system from the equilibrium position,

F(t) is a driving force applied to the oscillating system.

Equation (1) describes quite well the behavior of vibratissime mode oscillations with small amplitude [1].

When used as a C the NDA viscometer ball diameter d, immersed in a fluid with dynamic viscosity η and a density of ρ and sufficiently remote from the walls of the cell based on the solution of the Navier-Stokes equations can be found resistance Fcacting on an oscillating with frequency ω bulb immersed in liquid [8]:

Equation (2) can be reduced to the form:

Using (3), the mechanical resistance of the probe in the fluid rCand the added mass of liquid m can be expressed as follows:

We show that the parameters rCand m can be determined by measurements in accordance with the inventive method and device.

If the results of measuring the output parameters vibratissime (amplitude a, frequency ω and phase ϕ forced oscillations of the probe) will be determined rCand m, the dynamic viscosity and the density of the liquid can be calculated by simultaneous solution of the equations (4) and (5).

To determine rCand m based on measurements using vibratissime can be used the following method.

When excited by a sinusoidal oscillation of the probe vibratissime in the air the natural frequency of its oscillations ω0can be dostat who offered for practical purposes the accuracy is calculated by the formula [7]:

where In - the effective stiffness,

M - the effective mass of the system.

If the perturbing force is changed according to the harmonic law:

the steady-state forced oscillations of the probe vibratissime are also harmonic with the same angular frequency [7]:

where

At the resonant frequency ωpthat at small damping is also very close to ω0the amplitude of oscillation of the probe is calculated by the equation (9), equal to:

At zero frequency the static displacement of the probe And0is:

From equations (11) and (12) it is easy to determine the mechanical quality factor Q of the vibrating system:

Here you can find the mechanical impedance of the vibrating system of vibratissime fluctuations in the probe viscometer in the air:

Here Qinthe q of the vibrating system in the air,

ARVthe oscillation amplitude of the probe when the resonance in the air,

resonance frequency of oscillations is part of the system in the air.

The parameters b, M, Qineasily determined by standard methods and with respect to the claimed subject matter are determined at the stage of calibration of the device.

Immersion probe viscometer in the liquid, the amplitude AndR jits oscillations at the resonant frequency will be equal to:

Here ωR jresonance frequency of the oscillating system when the immersion of the probe into the liquid.

Detecting relative changes in resonance frequency and amplitude of oscillation of the probe when immersed him in the analyzed fluid, from equations (14)...(17) we obtain:

Measuring AndR j/ARVthat ωR jRVand knowing rinand M solution of the system of equations (18) and (19) we find the values of rCand m.

After determining these parameters by solving the system of equations (4) and (5) are calculated viscosity η and the density ρ the investigated liquid. If the measurements were conducted at a fixed temperature, and in a certain temperature range, the method allows to determine the dependence of these parameters of the liquid temperature. In particular, these mathematical operations can issue lunatica automatically using, for example, a computer or microcontroller.

To determine thermophysical properties of liquids: thermal diffusivity and heat capacity C and thermal conductivity λ - consider the heat equation to declare a thermodynamic system.

Declare thermodynamic system is schematically depicted in figure 4. We will adopt the following notation and terms:

- cuvette 8 has an inner radius R, height H, mass Mtoheat withtothermal diffusivity andto,

- spherical probe 14, coaxially located in the center of the cell at a distance of (H-z0from its bottom, has a diameter d, mass MCvolume VCheat withCthermal diffusivity andC;

- analyzed liquid 9 has a mass MWwith thermal diffusivity andW;

- rod probe 18 is made of insulating material;

TK and TC is the temperature of the probe and the bottom of the cell, respectively;

W(t) is the heat flux depending on time t, attached to the bottom of the cuvette;

W1(t) and W2(t) heat flow leaving from the side walls and the upper edges of the cell into the environment. W3(t) is the heat flux, passing through the stem of the probe.

Of most interest are thermal processes in the investigated liquid during its cooling from below, when we can neglect the phenomena of convec the AI in the liquid. If thermal diffusivity of liquids andWa lot less temperatureprofile the cell and probe (atoand aCrespectively), while the outer surface of the probe and the inner surface of the cell can be replaced by isothermal surfaces with temperatures TCand Ttorespectively.

With appropriate engineering performance of a thermodynamic system, such as when the condition of the insulation of the side walls of the cell (Ref. 26), flows W1(t), W2(t) and W3(t) can be neglected, and a physical model of a thermodynamic system takes the form shown in figure 5.

Denote by T(r, z, t) is the temperature difference between the liquid temperature and the initial temperature Tabout, r, and z - coordinates of the specified point of a liquid in a cylindrical coordinate system, t is the current time.

For an isotropic liquid is just the heat equation [7]:

Using this equation, you can solve either the direct problem, i.e. according to equation (22) when known asWfind the function T(r, z, t), or the inverse problem, that is experimentally known function T(t) and findW(Tcf), where

The solution of the direct problem for a given change in temperature of the cell Tto(t)=T0-pt (R>0) has the form:

where μk- the roots of the equation J0(μ)=0; (J0I , J1- the Bessel functions of zero and first order; R - coefficient of proportionality depending on the temperature of time; T0- the initial temperature of the cuvette;

The solution of the inverse problem of determining andW(Tcf) on experimentally known function T(t) can be greatly facilitated using thermodynamic system of regular thermal regime of the second kind [3]. In this case, thermodynamic behavior of the system depending on the temperature change of the cell TC(1) (set by operator) describes two integral thermodynamic parameters:

It is the shape factor, which depends only on the geometry of a thermodynamic system and has rank m2,

Θ - cooling rate, which characterizes the overall temporal inertia cooling medium and having a dimension s-1.

End of the cylinder, the coefficient K is determined by the formula [3]:

where R and N is the radius and height of the cell in this case.

If to consider a thermodynamic system known To and Θ. aWis defined as:

or

Using the regular approximation is th mode, you can easily find the solution of the direct problem as the response of the integrating circuit to the input action. In particular, when the temperature of the cell TC(t)=T0-pt (p>0) we obtain:

When t·Θ≫1, that is, after a sufficiently long time after the start of cooling, this equation is greatly simplified:

If necessary, the problem can be solved in exponential input action without conditions simplify the equation.

The shape factor used To a thermodynamic system can either be calculated [3], or determined experimentally when filling a thermodynamic system fluid with a known dependence andW(T)

By the well-known K-factor for the considered thermodynamic system can be defined asW(Tcffor the investigated liquid:

where Tcf- the average temperature of the liquid at the time of measurement.

Thus, according to the measurement results and the above calculations can be determined claimed process parameters viscosity fluid ηits density ρ, thermal diffusivity andWthe change in temperature of the cell Tto(t), probe TC(t) and the average temperature of the liquid T cf(t).

With the found parameters, provided the definition of the heat flux supplied to the cell, may also be determined based on the average fluid temperature Tcp(t) is its heat capacity is CWand thermal conductivity λW.

For shown in figure 5 thermodynamic system heat balance equation can be represented as follows:

or

where ΔQW- the number of the heat transfer fluid during Δt.

Possible definition of the heat flux W(t) described above in the device (p.8-9).

If the difference between Tcp1-Tcp2small, then from (32) we obtain:

that is, we find the dependence of the heat capacity of the fluid temperature.

As shown previously, by solving the system of equations (4) and (5) may be determined by the density of the liquid. In addition, as is well known [7], thermal diffusivity andWis determined by the expression:

From here you can determine the conductivity of the liquid.

Thus, the claimed method in the process of joint measurements of oscillatory process of the vibration sensor and the temperature of the cell and probe vibratissime poses the s simultaneously to determine the following parameters of the investigated liquid (including, depending on the temperature):

dynamic viscosity ηdensity ρ,

thermal diffusivity andW.

The results of these measurements are provided to determine the heat flow can be measured depending on the temperature:

specific heat C,

coefficient of thermal conductivity λ.

The inventive method and device provide:

1. The possibility of simultaneous determination of the main thermophysical properties of liquids using microdoses (of 0.15...0.2 ml) of the investigated liquids, which significantly reduces the analysis time and facilitates the disposal of the sample.

2. The possibility to study the properties of liquids, including multicomponent liquid media if the amplitude of oscillations of the probe, which is comparable with the characteristic size of the largest organic molecules that is of considerable interest in research in the field of molecular physics.

3. Investigation of low-temperature properties of fluids, including determination of the freezing temperature of engine oils and fuels with a depressant additives, using microdose (of 0.15...0.2 ml) of the investigated liquid.

Sources of information

1. Solov'ev A.N., Kaplun WAS vibrating method of measuring the viscosity of liquids. - Novosibirsk: Nauka, Siberian Department, 1970.

2. Cherednichenko GI, Freistetter G.B., Stupak PM Physicist who-chemical and thermo-physical properties of lubricants. - Leningrad: Khimiya, 1986.

3. Kondratyev G.M. Regular heat mode. - M.: Gostekhizdat, 1954.

4. RF patent for the invention №2183323 "Way to study low-temperature properties of multicomponent liquids and device for its implementation".

5. Mir GY Microprocessors in measuring devices. - M.: Radio and communication. - 1984.

6. Balashov, H.E. and D.V. Puzankov Microprocessors and microprocessor systems. - M.: Radio and communication. - 1981.

7. Jaworski BM, Detlef A.A. physics Handbook. - M.: Nauka, 1977.

8. Landau L.D., Lifshitz BM Hydrodynamics. - M.: Nauka, 1964.

1. The method of study of thermophysical properties of liquids, which consistently over time change and measure the temperature of the investigated liquid in the cell, and record the temperature-dependent physical parameters of the liquid, characterized in that the metal inside the cell in the investigated liquid post heat-insulated from the external environment of the metal probe vibratissime excited at a given frequency and with a given driving force, uniformly and continuously over time at a known law of change of the temperature of the cell at a rate greater than the rate setting process temperature changes of the investigated liquid in the cuvette, measure the temperature of the probe throughout a given range of temperature change of the cell, as well as the amplitude, and/or phase and/or frequency of oscillations of the probe and determine the density, viscosity and thermal diffusivity of fluid, depending on its temperature according to the equation of thermal conductivity of the liquid and the equation of forced oscillations of the probe vibratissime.

2. The method according to claim 1, characterized in that the temperature of the cell change by applying to it a known constant or monotonically and continuously time-varying heat flux and further define the heat capacity and thermal conductivity of the investigated liquid depending on the temperature of the heat balance equation of the liquid.

3. Device for the study of thermophysical properties of liquids, comprising a housing, which has United with DC sources two thermoelectric module with thermo-accumulating bases between them, the first of which is connected to an adjustable current source and has thermal contact with the cell cavity for accommodation of a measured fluid inside the cell in the liquid under study posted by the measuring transducer and temperature sensor temperature dependent physical parameter of the fluid, the outputs of which are connected to the input of device registration and management, the output of which is connected with the control input of the controlled current source, the second thermoelectric module is equipped with means of the heat sink, characterized in that the sensor of the temperature-dependent physical setting is made in the form of a metallic probe vibratissime placed in a liquid with the possibility of insulation from the external environment, the transmitter temperature probe integrated in the probe, and the second measuring transducer temperature is placed in the bottom of the metal pan, insulated from the external environment.

4. The device according to claim 3, characterized in that the measuring transducer temperature probe-type thermocouple measuring junction which is placed in the probe and the reference junction is cooled housing vibratissime.

5. The device according to claim 3, characterized in that the second measuring transducer temperature of the cell is made in the form of a thermocouple measuring junction which is placed in the bottom of the cell and the reference junction temperature-controlled.

6. The device according to claim 3, characterized in that between the first thermoelectric module and the cuvette is placed with providing thermal contact between the heat flow sensor, the output of which is connected to the input of device registration and management.

7. The device according to claim 3, characterized in that the probe vibratissime made in the form of a ball of copper or silver having a protective film coating.

8. The device according to claim 3, characterized in that the rod probe viscos the meter is made in the form of a capillary tube of insulating material, for example, glass or ceramics, which are inside the capillary conductors of thermocouple.

9. The device according to claim 3, characterized in that vibratissime cuvette and placed in the device can move relative to each other.



 

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The invention relates to the determination of the types of fusible clays and can be used in exploration and production and mining industry, and also in those industries that use clay

The invention relates to a device for studying the phase behavior of hydrocarbons and can be used in the oil and gas industry for research purposes when establishing the basic parameters of deep and reconstituted samples of reservoir oil and gas-condensate systems, refer to the thermobaric conditions of their occurrence

The invention relates to the field of molecular physics, technology and physics of polymers transparent and semi-transparent in the optical range of frequencies

The invention relates to the study of phase transformations in the solution-melt environments, namely, to methods for determining the temperature of crystallization in the solution-melt (the liquidus temperature)

The invention relates to a testing technique

The invention relates to physico-chemical analysis and can be used for rapid analysis in the production of alloys in metallurgy, electrochemistry and t

The invention relates to thermochemical measurements

FIELD: investigating or analyzing materials.

SUBSTANCE: thermograph comprises differential thermocouple and aluminum thermal unit provided with two symmetrically arranged cylindrical holes for crucible with specimen and standard. The crucibles are made of cylinders with caps provided with copper pipes for hot junctions of Chromel-cupel thermocouples. The wires of the thermocouples are housed in the two-channel ceramic rods. The thermoelectric heating of the unit is provided with the use of temperature-sensitive resistor made of nichrome wire. The unit is mounted in the steel sealed housing with a lid and provided with a device for locking it inside the housing during cooling and heating.

EFFECT: simplified design and enhanced accuracy of measuring.

1 dwg

FIELD: polymorph processes in metals and electro-conducting materials.

SUBSTANCE: method of measuring temperature of polymorph transformation is based upon heating for hardening till temperature providing free sag of rigidly tight sample. The temperature should correspond to α→β polymorph transformation.

EFFECT: improved precision of measurement.

5 dwg

FIELD: measurement technology.

SUBSTANCE: device has trier provided with holder and measuring probe provided with thermocouple placed inside the trier. Thermocouple is used which has time constant less than 1,5 sec. Volume of part of thermocouple submerged into salt melt relates to volume of cup of the trier as (5x10-3-10-2):1. Precise value of temperature can be achieved as well as high degree of reproducibility.

EFFECT: improved precision; prolonged service life of thermocouple.

9 cl, 4 dwg

FIELD: test equipment.

SUBSTANCE: metal probe of vibration viscosimeter is disposed inside metal dish in tested fluid to make it thermally isolated from outer space. Viscosimeter is excited with preset frequency and with preset force. Temperature of the dish is changed monotonously and continuously to follow specified rule at speed to exceed speed of establishing processes of change in temperature of tested liquid inside the dish. Temperature of the probe is measured within whole preset range of changes in temperature of the dish as well as amplitude and/or phase and/or frequency of oscillations of the probe. Density, viscosity, thermal conductivity, heat capacity and thermal diffusivity of tested fluid are measured depending on fluid's temperature from the relation of heat diffusivity of fluid and from the relation of viscosimeter's probe forced oscillations. The main feature of the device realizing the method has to be the metal probe of viscosimeter made in form of copper ball or silver ball disposed in fluid for thermal insulation onto rod made of thermo-insulating material. Measuring converter of probe's temperature is made in form of thermocouple and built inside probe. Second measuring converter of probe's temperature, also made in form of thermocouple, is placed onto bottom of metal dish thermally insulated from environment.

EFFECT: improved efficiency of test.

10 cl, 5 dwg

FIELD: inspection of quality of oil products.

SUBSTANCE: permanent-weight lubricant is subject to heating in thermo-stable glass cup at three temperatures at least, which temperatures exceed that one of beginning of oxidation and then it is subject to mixing by glass mixer at constant speed during 12 hours or less. Samples for photometry are selected in equal time intervals. Factor of absorption of light flux by oxidized oil Ability to evaporation is measured by weighing sample before and after test. Graphical dependences of theses parameters are built relatively temperature of testing. Thermal-oxidative stability of lubricant is determined by critical temperature of service ability, by temperature of beginning of oxidation and by temperature of beginning of oxidation.

EFFECT: improved efficiency of measurement.

2 dwg

FIELD: investigating or analyzing materials.

SUBSTANCE: method comprises heating specimens to be analyzed with a rate of 10 deg/min, using standard initial polymineral clays, selecting temperature intervals 20-200°C, 600-800°C, and 20-100° C from the thermo-analytic curves of the standards, determining the reference values in the intervals, determining mass losses, and choosing maximum values of the mass losses in the intervals for the calculation of the fraction ration of clays.

EFFECT: enhanced accuracy of measurements.

6 dwg, 1 tbl, 6 ex

FIELD: measurement technology.

SUBSTANCE: method involves carrying out experimental temperature measurements of cooling liquid avalanche dissociation on hot surface under static conditions, without liquid flow being arisen.

EFFECT: simplified cooling liquid quality control process; reduced tested substance quantity in samples under test; personnel safety in carrying out tests.

1 dwg

FIELD: measuring technique.

SUBSTANCE: method comprises testing two samples of the lubricant of the same mass, the first sample being tested without catalyzer and the second sample being tested in the presence of catalyzer, determining transparency coefficient by means of photometric measurements, plotting time dependences of the transparency coefficient, and determining oxidation stability of the lubricant from the equation presented.

EFFECT: enhanced precision.

3 dwg, 1 tbl

FIELD: measuring technique.

SUBSTANCE: while warming sample up, average value of square of voltage of thermal electrical; fluctuations is measured at terminals of measuring converter. Maximal value, which corresponds to glass transition temperature, is measured, at which temperature the value of dielectric permeability is found and value of hardness coefficient is calculated. Method can be used for measurement of equilibrium hardness coefficient of polymer chains for polymers in unit.

EFFECT: improved precision of measurement.

1 dwg, 6 tbl

FIELD: thermometry.

SUBSTANCE: method provides usage of temperature detectors to transform electric signal, and identification of type of phase transition. Electric Signal from temperature detector is corrected for value of electric signal which is generated by phase transition of material. Correcting electric signal is achieved by means of additional probe.

EFFECT: improved precision of measurement.

4 cl, 9 dwg

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