CN103728340B - A kind of method and experimental provision being applicable to flow model high-temperature, high pressure fluid Measured Results of Thermal Conductivity - Google Patents

Abstract

The invention discloses a kind of method and the experimental provision that are applicable to flow model high-temperature, high pressure fluid Measured Results of Thermal Conductivity.Described experimental provision comprises developmental tube, Heated Copper electrode A and Heated Copper electrode B, thermometric hybrid chamber A and thermometric hybrid chamber B, wall temperature thermopair, fluid temperature (F.T.) thermopair A and fluid temperature (F.T.) thermopair B, copper electrode lead-in wire A and copper electrode lead-in wire B, adaptor three-way A and adaptor three-way B, also comprises the coated screening heat shielding of developmental tube outer wall and thermal insulation material.The present invention carries out good insulation to developmental tube, effectively reduce the heat transfer free convection in experimentation and radiation heat loss, make experimental data error less, for design, the application obtaining coefficient of heat conductivity experimental data and coefficient of heat conductivity accurately provides strong foundation.Described experimental provision provides strong help to novel cooling manner research, is also the accurate measuring of high temperature high pressure liquid coefficient of heat conductivity under 0 ~ 7MPa pressure, provides the feasibility of experiment.

Description

A kind of method and experimental provision being applicable to flow model high-temperature, high pressure fluid Measured Results of Thermal Conductivity

Technical field

The present invention relates to a kind of method and the device that are applicable to high-temperature, high pressure fluid Measured Results of Thermal Conductivity, be specifically related to based on laminar flow, constant heat flow border, flowing and thermal boundary layer simultaneously full-blown condition get off to measure the coefficient of heat conductivity of 0-7MPa fluid under pressure under flow state.Be mainly used in the aspect such as association area and general fluid basal heat physical measurement that Aero-Space, the energy, automobile and petrochemical complex etc. lack physical properties of fluids data.

Background technology

Along with the raising of temperature before aero-turbine and compressor pressure ratio, the cooling air temperature of drawing from pneumatic plant rear class also improves gradually, and this reduces causing the cooling quality of refrigerating gas, brings great challenge to the cooling of engine thermal end pieces.When cold air consumption and cooling structure cannot significantly change at short notice, utilize that the height of aviation fuel is heat sink to be cooled cooling-air in advance, reduce the temperature of refrigerating gas, not only can improve the cooling quality of refrigerating gas, simultaneously, aviation fuel after intensification is easier to atomization and burning, brings larger effectively to utilize space.But, under supercritical pressure, aviation kerosene there will be the Flow-induced vibration characteristic different under subcritical pressure boiler, and in order to study hydrocarbon fuel flowing and heat transfer characteristic under supercritical pressure, the basal heat physical property obtaining fuel has important construction value and researching value.And due to the difference of composition between various oil product, lack the coefficient of heat conductivity experimental data of aviation kerosene RP-3 both at home and abroad, this is unfavorable for the investigation and application of this novel cooling manner.Some research institutions coefficient of heat conductivity adopting experimental technique that is static, transient state and relevant device (transient hot wire technique etc.) to measure fluid both at home and abroad more, but in a static condition, aviation kerosene under the high temperature conditions, longer residence time can cause irreversible impact to kerosene composition, the measurement result of impact " time downstream " test point.In addition, the experimental facilities of static method is often very complicated, transient experiment often relates to the stable of thermostatic bath, and this process need longer time just can reach balance and stable, and this method that all significantly limit this type is in the use of measuring flow thermal conductivity coefficient under high-temperature and high-pressure conditions.The somewhat complex design such as constant temperature oil bath and electronic control system, increases difficulty of test and development cost.

Summary of the invention

The present invention, in order to solve problems of the prior art, provides a kind of assay method and the experimental provision that are applicable to flow model high-temperature, high pressure fluid coefficient of heat conductivity, utilizes flow model high-temperature, high pressure fluid Thermal Conductivity Test Installation to measure flow thermal conductivity coefficient.Good insulation is carried out to developmental tube, effectively reduces the heat transfer free convection in experimentation and radiation heat loss, make experimental data error less, for design, the application obtaining coefficient of heat conductivity experimental data and coefficient of heat conductivity accurately provides strong foundation.Described experimental provision provides strong help to novel cooling manner research, is also the accurate measuring of high temperature high pressure liquid coefficient of heat conductivity under 0 ~ 7MPa pressure, provides the feasibility of experiment.

First the present invention provides a kind of experimental provision for flow model high-temperature, high pressure fluid Measured Results of Thermal Conductivity, and described experimental provision comprises developmental tube, is coated on the thermal insulation material of developmental tube outer wall; The inlet end of described developmental tube connects adaptor three-way A by thermometric hybrid chamber A, and endpiece connects adaptor three-way B by thermometric hybrid chamber B; The two ends of the developmental tube between described thermometric hybrid chamber A and thermometric hybrid chamber B are provided with again Heated Copper electrode A and Heated Copper electrode B respectively.Described thermometric hybrid chamber A connects first port of adaptor three-way A, and second port of adaptor three-way A connects fluid temperature (F.T.) thermopair A, and the 3rd port is as fluid intake A; Described thermometric hybrid chamber B connects first port of adaptor three-way B, and second port of adaptor three-way B connects fluid temperature (F.T.) thermopair B, and the 3rd port is as fluid egress point B.Fluid is flowed into by import A, enters thermometric hybrid chamber A through adaptor three-way A, bottom-uply flows through test section, through the thermometric hybrid chamber B in exit, is finally flowed out by outlet B.

Described fluid temperature (F.T.) thermopair A and fluid temperature (F.T.) thermopair B inserts in thermometric hybrid chamber A and thermometric hybrid chamber B respectively.

The thermocouple wire of described wall temperature thermopair evenly lays along the wall isotherm of developmental tube.Based on above-mentioned experimental provision, the present invention also provides a kind of experimental technique, and described method comprises the steps:

The first step, Preparatory work of experiment:

Measurement accuracy also records internal diameter d, the length L of developmental tube _shortalong pipe range direction uniform welding 20 groups, often organize the complete wall temperature thermopair of the calibrating of 2, the Heated Copper electrode A of arranging with developmental tube import A place, for benchmark, is measured the position of each wall temperature thermocouple welding point, to determine the distribution situation of wall temperature thermopair along pipe range;

According to determine until the viscosity of fluid measured this fluid reynolds number Re number for 600 to 1200 time different temperatures corresponding to flow range, to be regulated the flow treating fluid measured in measuring process, experimentation should ensure that Re number is in this interval;

To developmental tube outer wall parcel thermal insulation material and screening heat shielding, carry out abundant insulation;

Check that fluid temperature (F.T.) thermopair and wall temperature thermopair are to ensure that it is working properly;

Second step, measure flow thermal conductivity coefficient to be measured:

First fix hydrodynamic pressure to be measured, regulate flow and the temperature for the treatment of fluid measured, reach discreet value (800-1000) to make the import reynolds number Re of developmental tube.After temperature, pressure, flow are all stable, gather and record the temperature of fluid, pressure and flow value, writing time is greater than 30s, and is averaging processing image data, obtains total flow, each wall temperature put and fluid inlet and outlet temperature after process.According to flow method thermal conductivity measurement formula:

$\mathrm{\λ}=\frac{11\·{\mathrm{Cp}}_{\mathrm{ave}}\·m\·(T_{\mathrm{out}}-T_{\mathrm{in}})}{48\mathrm{\π}\·\mathrm{L\ΔT}}---\left(20\right)$

Treat the coefficient of heat conductivity of fluid measured under calculating this temperature case, wherein Q is the total amount of heat be added on tube wall, and L is test pipe range, and Δ T is defined as the difference of inside pipe wall temperature and average temperature of fluid section, and m is the mass rate of fluid, T _inwith T _outthe temperature that fluid is imported and exported at developmental tube respectively, Cp _avefor the average specific heat at constant pressure of fluid.

3rd step, changes developmental tube inlet temperature, repeats second step, carries out the measurement of the coefficient of heat conductivity of next temperature, until fluid temperature (F.T.) to be measured reaches the required upper limit (20 DEG C≤T≤600 DEG C) measured;

4th step: regulating system pressure, repeat second step and the 3rd step, carry out the thermal conductivity measurement of next pressure, until hydrodynamic pressure to be measured reaches the required upper limit measured, flow thermal conductivity coefficient variation with temperature relation under different pressures (0 ~ 7MPa) can be obtained thus.

The invention has the advantages that:

(1) flow method is adopted to measure the coefficient of heat conductivity of fluid, and static experiment can only measure fluid coefficient of heat conductivity in a static condition, feature due to hydrocarbon fuel: under high temperature, irreversible change can occur, all static measurements can cause the experimental data " distortion " on follow-up time point.And flow rule effectively avoids this situation that occurs;

(2) by effective insulation, heat transfer free convection thermal loss and radiation heat loss is effectively reduced.

(3) this device can measure the coefficient of heat conductivity of fluid under high temperature (20 DEG C≤T≤600 DEG C) high pressure (0-7MPa), and the relatively existing experimental facilities of measurement range is improved largely.

(4) compared to the transient state hot line measurement mechanism of traditional measurement flow thermal conductivity coefficient, the new measurement based on this measuring method has that structure is simple, the Research and development and production cycle is short, to outstanding advantages such as electromagnetic interference (EMI) are insensitive.Significantly, this measurement device flow thermal conductivity coefficient is adopted greatly can to reduce energy consumption.

Accompanying drawing explanation

The experimental provision structural representation of Fig. 1 flow method heat conducting coefficient measuring provided by the invention;

Fig. 2 is the structural representation of fluid inlet and outlet thermometric hybrid chamber in the present invention;

Fig. 3 is the method for arranging schematic diagram of the warm galvanic couple of developmental tube upper wall;

Fig. 4 is that schematic diagram arranged by the warm galvanic couple of developmental tube upper wall;

Fig. 5 adopts Double-Line Method to edit result to recording result.

In figure:

1. developmental tube; 2. Heated Copper electrode A; 3. Heated Copper electrode B; 4. thermometric hybrid chamber A; 5. thermometric hybrid chamber B; 6. wall temperature thermopair; 7. fluid temperature (F.T.) thermopair A; 8. fluid temperature (F.T.) thermopair B; 9. copper electrode lead-in wire A; 10. copper electrode lead-in wire B; 11. adaptor three-way A; 12. adaptor three-way B; 13. hide heat shielding; 14. thermal insulation materials.

Embodiment

Below in conjunction with accompanying drawing, the present invention is described in detail.

The method being applicable to measure flow thermal conductivity coefficient provided by the invention is based under laminar flow, constant heat flow border, flowing and thermal boundary layer simultaneously full-blown condition, the convection heat transfer of fluid in circular channel mainly diffusion process, only relevant with flow thermal conductivity coefficient and caliber, therefore, the invention provides a kind of method and the experimental provision that are applicable to flow model high-temperature, high pressure fluid Measured Results of Thermal Conductivity, by the convection transfer rate of Accurate Measurement tube wall and tube fluid, and then draw the coefficient of heat conductivity of fluid.Theory deduction process is as follows:

The momentum conservation equation of fluid is

$\mathrm{\ρu}\frac{\∂u}{\∂x}+{\mathrm{\ρv}}_r\frac{\∂u}{\∂r}=-\frac{\mathrm{dp}}{\mathrm{dx}}+\frac{1}{r}\frac{\∂}{\∂r}\left(\mathrm{r\μ}\frac{\∂u}{\∂r}\right)---\left(1\right)$

Define according to full-blown velocity profile, obviously have ν _r=0 He and u is only the function of r.So formula (1) can be simplified to:

$0=-\frac{\mathrm{dp}}{\mathrm{dx}}+\frac{1}{r}\frac{\∂}{\∂r}\left(\mathrm{r\μ}\frac{\∂u}{\∂r}\right)---\left(2\right)$

Because stress has nothing to do with certain radius r a bit located in pipe, formula (2) directly can obtain desired velocity function for twice to r integration.

Boundary condition is:

$\frac{\mathrm{du}}{\mathrm{dr}}=0,r=0$

u＝0,r＝R（3）

Obtain velocity profile equation:

$u=\frac{R^2}{4\mathrm{\μ}}(-\frac{\mathrm{dp}}{\mathrm{dx}})(1-\frac{r^2}{R^2})---\left(4\right)$

After ignoring pressure gradient and endogenous pyrogen, the energy equation of normal physical property ideal fluid can simplify writing in cylindrical-coordinate system:

$\frac{u}{a}\frac{\∂t}{\∂x}=\frac{1}{r}\frac{\∂}{\∂r}\left(r\frac{\∂t}{\∂r}\right)+\frac{{\∂}^{2}t}{\∂x^2}---\left(5\right)$

Negligible axial heat conduction item again can write:

$\frac{u}{a}\frac{\∂t}{\∂x}=\frac{1}{r}\frac{\∂}{\∂r}\left(r\frac{\∂t}{\∂r}\right)---\left(6\right)$

Above formula (6) is the fundamental differential of inner tube layer stream.First, cartesian coordinate system is set up to pipe, u, v in above formula represent the speed component in x, y direction, i.e. the fluid component velocity of streamwise and the fluid component velocity perpendicular to flow direction, and a is thermal diffusivity, μ is kinetic viscosity, r is the radius that in pipe, certain is a bit located, and R is pipe inside radius, and p is hydrodynamic pressure, t is temperature, v _rfor the fluid velocity of a certain radius, ρ is for treating measured fluid density.

Boundary condition under constant heat flow condition is:

r＝R,t＝t _w

$r=0,\frac{\∂t}{\∂r}=0---\left(7\right)$

Formula (7) is substituted into formula (6) can obtain:

$\frac{1}{r}\frac{\∂}{\∂r}\left(r\frac{\∂t}{\∂r}\right)=\frac{2v}{a}(1-\frac{r^2}{R^2})\frac{{\mathrm{dt}}_b}{\mathrm{dx}}---\left(8\right)$

Above formula (8) directly carries out twice integration to r, and recycling boundary condition determines two integration constants, can obtain following temperature profile:

$t=t_w-\frac{2v}{a}\left(\frac{{\mathrm{dt}}_b}{\mathrm{dx}}\right)(\frac{{3R}^2}{16}+\frac{1}{16}\frac{r^4}{R^2}-\frac{1}{4}{r}^2)---\left(9\right)$

The expression formula of medial temperature and average velocity is utilized to obtain:

$t_w-t_m=\frac{11}{96}\frac{2v}{a}\left(\frac{{\mathrm{dt}}_b}{\mathrm{dx}}\right)R^2---\left(10\right)$

And the hot-fluid q on wall _wfor:

$q_w=h(t_w-t_m)=h\·\frac{11}{96}\frac{2v}{a}\left(\frac{{\mathrm{dt}}_b}{\mathrm{dx}}\right)R^2---\left(11\right)$

T in above formula _bfor average temperature of fluid section, t _wfor tube wall temperature, t _mfor the medial temperature of fluid, h is convection transfer rate in pipe.

By formula (9) to r differentiate, in conjunction with Fourier Heat Conduction law, and with formula (11) simultaneous, can obtain:

$h=\frac{48}{11}\frac{\mathrm{\λ}}{d}---\left(12\right)$

Have according to Newtonian Cooling formula:

$h=\frac{q}{\mathrm{\ΔT}}---\left(13\right)$

Heat flow density q is:

$q=\frac{Q}{\mathrm{\πdL}}---\left(14\right)$

Wherein, d is bore (diameter).

So when meeting following hypothesis: (1) fluid is in laminar flow state in pipe; (2) fluid fully develops; (3) constant heat flow boundary condition; (4) fluid thermophysical property is constant; (5), when ignoring natural convection, can treat that the coefficient of heat conductivity λ of fluid measured is by formula (12), formula (13) and formula (14):

$\mathrm{\λ}=\frac{11\·Q}{48\·\mathrm{\π}\·L\·\mathrm{\ΔT}}---\left(15\right)$

In formula, L is test pipe range, and Δ T is the difference (being called for short wall fluid temperature difference Δ T) of inside pipe wall temperature and average temperature of fluid section, and qualitative temperature gets the arithmetic mean temperature importing and exporting oil temperature, and the total amount of heat Q be added on tube wall is:

Q＝Cp _ave·m·(T _out-T _in)（16）

Therefore when constant heat flow heats and meets normal physical property hypothesis, the convection transfer rate of fluid and wall is constant, can be obtained by formula (11):

t _w-t _b＝const（17）

Namely have:

$\frac{{\mathrm{dt}}_w}{{\mathrm{dt}}_x}=\frac{{\mathrm{dt}}_b}{{\mathrm{dt}}_x}---\left(18\right)$

So,

$\frac{\∂t}{\∂x}=\frac{d{t}_w}{{\mathrm{dt}}_x}=\frac{{\mathrm{dt}}_b}{d{t}_x}---\left(19\right)$

Cp in formula _avefor tube fluid mean specific heat, T _outand T _inbe respectively outlet temperature and the inlet temperature of tube fluid.In experiment, key accurately obtains wall-fluid temperature difference Δ T.From formula (19), fluid temperature (F.T.) is identical with pipe range change curve slope with wall surface temperature with the slope of pipe range change curve, then along pipe range, slope (slope is oil temperature rate of curve) is determined to wall temperature point and carry out linear regression to reduce stochastic error, draw the difference of the intercept between wall temperature curve and fluid temperature (F.T.) curve, this difference is wall temperature-fluid temperature difference Δ T, can obtain the coefficient of heat conductivity of fluid under qualitative temperature by formula (15).

Based on above-mentioned principle, the invention provides a kind of experimental provision being applicable to high-temperature, high pressure fluid Measured Results of Thermal Conductivity, as shown in Figure 1, described experimental provision comprises developmental tube 1, Heated Copper electrode A 2 and Heated Copper electrode B 3, thermometric hybrid chamber A4 and thermometric hybrid chamber B5, wall temperature thermopair 6, fluid temperature (F.T.) thermopair A7 and fluid temperature (F.T.) thermopair B8, copper electrode lead-in wire A9 and copper electrode lead-in wire B10, adaptor three-way A11 and adaptor three-way B12, in order to better be incubated developmental tube 1, also comprise the coated screening heat shielding 13 of developmental tube 1 outer wall and thermal insulation material 14.The inlet end of described developmental tube 1 connects adaptor three-way A11 by thermometric hybrid chamber A4, and endpiece connects adaptor three-way B12 by thermometric hybrid chamber B5; The two ends of the developmental tube 1 between described thermometric hybrid chamber A4 and thermometric hybrid chamber B5 are provided with again Heated Copper electrode A 2 and Heated Copper electrode B 3 respectively.Described thermometric hybrid chamber A4 connects first port of adaptor three-way A11, and second port of adaptor three-way A11 connects fluid temperature (F.T.) thermopair A7, and the 3rd port is as fluid intake A; Described thermometric hybrid chamber B5 connects first port of adaptor three-way B12, and second port of adaptor three-way B12 connects fluid temperature (F.T.) thermopair B8, and the 3rd port is as fluid egress point B.Fluid is flowed into by import A, enters thermometric hybrid chamber A4 through adaptor three-way A11, bottom-uply flows through developmental tube 1, through the thermometric hybrid chamber B5 in exit, is finally flowed out by outlet B.Two described Heated Copper electrode A 2 are connected power supply respectively by copper electrode lead-in wire A9 with copper electrode lead-in wire B10 with B3, provide direct current supply voltage.

Described developmental tube 1 is vertically placed, and adopts the mode that fluid flows from the bottom up.In order to Measurement accuracy developmental tube 1 imports and exports fluid temperature (F.T.), import and export at developmental tube 1 and weld two fluid thermometric hybrid chamber A4 and thermometric hybrid chamber B5 respectively, in thermometric hybrid chamber A4 and thermometric hybrid chamber B5, installed two-layer 200 object metal screens respectively additional abundant blending is carried out to incoming flow.Described thermometric hybrid chamber A4 connects first port of adaptor three-way A11, and second port of adaptor three-way A11 connects fluid temperature (F.T.) thermopair A7, and the 3rd port is as fluid intake A.Described thermometric hybrid chamber B5 connects first port of adaptor three-way B12, and second port of adaptor three-way B12 connects fluid temperature (F.T.) thermopair B8, and the 3rd port is as fluid egress point B.Fluid is flowed into by import A, enters thermometric hybrid chamber A4 through adaptor three-way A11, bottom-uply flows through developmental tube 1 section, through the thermometric hybrid chamber B5 in exit, is finally flowed out by outlet B.

As shown in Figure 2, the structure of described thermometric hybrid chamber A4 or thermometric hybrid chamber B5 is identical, there is the pipeline that three sections of internal diameters are different, internal diameter is respectively d1, d2 and d3, d1>d3>d2, the internal diameter d2 of interlude is minimum, and this section arranges metal screen, and described metal screen can be fixed on corresponding pipeline section.Internal diameter is that the pipeline section of d1 and corresponding adaptor three-way are welded and fixed, and internal diameter is that the pipeline section of d3 and developmental tube are welded and fixed.

Described fluid temperature (F.T.) thermopair A7 and fluid temperature (F.T.) thermopair B8 inserts in thermometric hybrid chamber A4 and thermometric hybrid chamber B5 respectively, and fluid temperature (F.T.) thermopair A7 and fluid temperature (F.T.) thermopair B8 is all through calibrating, and gauging error is 0.1K; The diameter of thermocouple wire is 1mm.As shown in Figure 4, in order to measure the change of wall surface temperature with pipe range, along uniform welding on developmental tube 1 20 groups, often organize 2 wall temperature thermopairs 6, the thermocouple wire of wall temperature thermopair 6 lays along the wall isotherm of developmental tube 1, often organize the concrete arrangement form of two wall temperature thermopairs 6 as shown in Figure 3, the thermocouple wire of two wall temperature thermopairs 6 is separately fixed at two points relative on the same circular section of developmental tube 1 outer wall, to reduce wall temperature thermopair 6 temperature measurement error as far as possible.Every wall temperature thermopair 6 is all through calibrating, and gauging error is 0.1K.

Described experimental provision produces Joule heat heat by directly adding alternating voltage on developmental tube 1.Treat that fluid measured enters developmental tube 1 by developmental tube 1 low-temperature end import A, 25mm place each fixed placement Heated Copper electrode A 2 and Heated Copper electrode B 3 is being about apart from described developmental tube 1 two ends, powered by stable dc power supply, described developmental tube 1 adopts Ni-based stainless steel steel pipe, utilize the tube resistor of stainless-steel tube self to carry out electrical heating, then export B outflow developmental tube 1 by temperature end.

For ensureing generation thermal loss little as far as possible in experimentation, developmental tube 1 outer wall parcel thermal insulation material 14, thermal insulation material 14 outer wrapping one deck hides heat shielding 13, to reduce thermal loss to greatest extent.Described screening heat shielding 13 is aluminium glue band.

Described thermal insulation material 14 adopts coefficient of heat conductivity to be 0.02W/(m*K) An Jiejia 5650 insulation material.

A kind of assay method being applicable to high-temperature, high pressure fluid coefficient of heat conductivity provided by the invention, comprises following step:

Step one: Measurement accuracy also records internal diameter d, the length L of developmental tube 1 _shortalong pipe range direction uniform welding 20 groups, often organize the complete wall temperature thermopair 6 of the calibrating of 2, the Heated Copper electrode A 2 of arranging with developmental tube 1 import A place, for benchmark, is measured the position of each wall temperature thermopair 6 pad, to determine the distribution situation of wall temperature thermopair 6 along pipe range;

Step 2: according to determine until the viscosity of fluid measured this fluid reynolds number Re number for 600 to 1200 time different temperatures corresponding to flow range, to be regulated the flow treating fluid measured in measuring process, experimentation should ensure that Re number is in this interval;

Step 3: to developmental tube 1 outer wall parcel thermal insulation material 14 and screening heat shielding 13, carry out abundant insulation;

Step 4: check that fluid temperature (F.T.) thermopair A7, fluid temperature (F.T.) thermopair B8 and wall temperature thermopair 6 are to ensure that it is working properly;

Step 5: measure flow thermal conductivity coefficient to be measured:

First fix hydrodynamic pressure to be measured, regulate flow and the temperature for the treatment of fluid measured, reach discreet value (800-1000) to make the import reynolds number Re of developmental tube 1.After temperature, pressure, flow are all stable, gather and record the temperature of fluid, pressure and flow value, writing time is greater than 30s, and is averaging processing image data, obtains flow m, each wall temperature T put after process _w,iand fluid inlet and outlet temperature T (i=40) _b,i(i=4).From formula (18), under laminar flow, in pipe, wall temperature is identical with the slope that fluid temperature (F.T.) changes with pipe range with the slope of pipe range change curve.Given this, according to the curve that fluid inlet and outlet temperature determination fluid temperature (F.T.) changes with pipe range, carry out determining slope one-variable linear regression to determine the relational expression that wall temperature changes with pipe range according to fluid temperature (F.T.) slope of a curve to wall temperature.The intercept difference of these two straight lines is wall-fluid temperature difference Δ T.According to flow method thermal conductivity measurement formula:

$\mathrm{\λ}=\frac{11\·{\mathrm{Cp}}_{\mathrm{ave}}\·m\·(T_{\mathrm{out}}-T_{\mathrm{in}})}{48\mathrm{\π}\·\mathrm{L\ΔT}}---\left(20\right)$

The coefficient of heat conductivity of fluid measured is treated under calculating this temperature case, wherein, Cp _avefor fluid average specific heat at constant pressure holds, m is the mass rate of fluid, T _inand T _outfor fluid inlet and outlet temperature, L is test section pipe range, and Δ T is defined as the difference of inside pipe wall temperature and average temperature of fluid section.

Step 6: change developmental tube 1 inlet temperature, repeats step 5, carries out the measurement of the coefficient of heat conductivity of next temperature, until fluid temperature (F.T.) to be measured reaches the required upper limit (20 DEG C≤T≤600 DEG C) measured;

Step 7: regulating system pressure, repeat step 5, step 6, carry out the thermal conductivity measurement of next pressure, until hydrodynamic pressure to be measured reaches the required upper limit (≤7MPa) measured, flow thermal conductivity coefficient variation with temperature relation under different pressures can be obtained thus.

Adopt thermal conductivity measurement method provided by the invention and existing Transient Method to carry out coefficient of heat conductivity demarcation to demarcation working medium toluene respectively, calibration result as shown in Figure 5, wherein λ _expfor the coefficient of heat conductivity that the present invention obtains, λ _pubfor the thermal conductivity value in standard database, calibration result shows, under the condition of identical temperature and uniform pressure, when in managing, Re number changes in the scope of 600-1200, the thermal conductivity measurement error of fluid is all within ± 2% error band.

Claims (2)

1. be applicable to an experimental provision for flow model high-temperature, high pressure fluid Measured Results of Thermal Conductivity, it is characterized in that: described experimental provision comprises developmental tube, is coated on the thermal insulation material of developmental tube outer wall; Wall isotherm along described developmental tube lays the thermocouple wire of wall temperature thermopair; The inlet end of described developmental tube connects adaptor three-way A by thermometric hybrid chamber A, and endpiece connects adaptor three-way B by thermometric hybrid chamber B; The two ends of the developmental tube between described thermometric hybrid chamber A and thermometric hybrid chamber B are provided with again Heated Copper electrode A and Heated Copper electrode B respectively; Described thermometric hybrid chamber A connects first port of adaptor three-way A, and second port of adaptor three-way A connects fluid temperature (F.T.) thermopair A, and the 3rd port is as fluid intake A; Described thermometric hybrid chamber B connects first port of adaptor three-way B, and second port of adaptor three-way B connects fluid temperature (F.T.) thermopair B, and the 3rd port is as fluid egress point B; Described fluid temperature (F.T.) thermopair A and fluid temperature (F.T.) thermopair B inserts in thermometric hybrid chamber A and thermometric hybrid chamber B respectively; In described thermometric hybrid chamber A and thermometric hybrid chamber B, install two-layer 200 object metal screens respectively additional blending has been carried out to incoming flow; Fluid is flowed into by import A, enters thermometric hybrid chamber A through adaptor three-way A, bottom-uply flows through test section, through the thermometric hybrid chamber B in exit, is finally flowed out by outlet B; Described thermal insulation material employing coefficient of heat conductivity is the insulation material of 0.02W/ (m*K).

2. based on the experimental technique being applicable to flow model high-temperature, high pressure fluid Measured Results of Thermal Conductivity of experimental provision according to claim 1, it is characterized in that: described method comprises the steps,

The first step, Preparatory work of experiment:

Measure and record internal diameter, the length of developmental tube, along pipe range direction uniform welding 20 groups, often organize the complete wall temperature thermopair of the calibrating of 2, the Heated Copper electrode A of arranging with developmental tube import A place is for benchmark, the position of each wall temperature thermocouple welding point is measured, to determine the distribution situation of wall temperature thermopair along pipe range;

According to determine until the viscosity of fluid measured this fluid reynolds number Re number for 600 to 1200 time different temperatures corresponding to flow range;

To developmental tube outer wall parcel thermal insulation material and screening heat shielding, carry out abundant insulation;

Check that fluid temperature (F.T.) thermopair and wall temperature thermopair are to ensure that it is working properly;

Second step, measure flow thermal conductivity coefficient to be measured:

First fix hydrodynamic pressure to be measured, regulate flow and the temperature for the treatment of fluid measured, reach discreet value 800-1000 to make the import reynolds number Re of developmental tube; After temperature, pressure, flow are all stable, gather and record the temperature of fluid, pressure and flow value, writing time is greater than 30s, according to flow method thermal conductivity measurement formula:

$\mathrm{\λ}=\frac{11\·{\mathrm{Cp}}_{ave}\·m\·(T_{out}-T_{in})}{48\mathrm{\π}\·L\mathrm{\Δ}T}$

The coefficient of heat conductivity of fluid measured is treated under calculating this temperature case, wherein, T _inwith T _outthe temperature that fluid is imported and exported at developmental tube respectively, Cp _avefor the average specific heat at constant pressure of fluid, L is test pipe range, and Δ T is the difference of inside pipe wall temperature and average temperature of fluid section, and m is the mass rate of fluid;

3rd step, changes developmental tube inlet temperature, and repeat second step, carry out the measurement of the coefficient of heat conductivity of next temperature, described temperature regulates within the scope of 20 DEG C ~ 600 DEG C;

4th step: regulating system pressure, repeats second step and the 3rd step, carries out the thermal conductivity measurement of next pressure, and obtain flow thermal conductivity coefficient variation with temperature relation under different pressures thus, described pressure selection range is 0 ~ 7MPa.