CN103728340A - Method and experimental device suitable for measuring heat conductivity coefficient of flowing high-temperature high-pressure fluid - Google Patents

Abstract

The invention discloses a method and an experimental device suitable for measuring the heat conductivity coefficient of flowing high-temperature high-pressure fluid. The experimental device comprises a test tube, a heating copper electrode A, a heating copper electrode B, a temperature measuring mixed cavity A, a temperature measuring mixed cavity B, a wall temperature thermocouple, a fluid temperature thermocouple A, a fluid temperature thermocouple B, a copper electrode lead A, a copper electrode lead B, a switchover tee joint A and a switchover tee joint B, and also comprises a heat shielding screen and a thermal insulation material wrapping the outer wall of the test tube. According to the experimental device, the test tube can be well subjected to heat insulation, so that loss of natural convection heat exchange and radiant heat can be effectively reduced in experiment, the experiment date error is small, and effective basis is provided for accurate experiment data of the heat conductivity coefficient and design and application of the heat conductivity coefficient. The experimental device provides effective help for research of a novel cooling manner, and also provides experimental feasibility for accurate experimental measurement of the heat conductivity coefficient of the high-temperature high-pressure fluid under pressure of 0-7MPa.

Description

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

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 will cause the cooling quality of refrigerating gas to reduce, and that gives engine thermal end pieces coolingly brings great challenge.In the situation that cold air consumption and cooling structure cannot significantly change at short notice, utilize that the height of aviation fuel is heat sink to carry out cooling to 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, has brought the larger space that effectively utilizes.But, under supercritical pressure, aviation kerosene there will be and different flowing and heat transfer characteristic under subcritical pressure boiler, and flow and heat transfer characteristic in order to study hydrocarbon fuel under supercritical pressure, the basal heat physical property that obtains fuel has important construction value and researching value.And due to the difference of composition between various oil products, lack the coefficient of heat conductivity experimental data of aviation kerosene RP-3 both at home and abroad, this is unfavorable for research and the application of this novel cooling manner.Both at home and abroad some research institutions adopt static, the experimental technique of transient state and the coefficient of heat conductivity that relevant device (thermal transient collimation method etc.) is measured fluid more, but under static condition, aviation kerosene is under hot 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 the longer time of this process need just can reach balance and stable, and this method that has all limited greatly 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, has strengthened 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 experimental provision that is 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.Developmental tube is carried out to good insulation, effectively reduce heat transfer free convection and radiation heat loss in experimentation, make experimental data error less, for obtaining design, the application of coefficient of heat conductivity experimental data and coefficient of heat conductivity accurately, provide strong foundation.To novel cooling manner, research provides strong help to described experimental provision, is also the accurate measuring of high temperature high pressure liquid coefficient of heat conductivity under 0～7MPa pressure, and the feasibility of experiment is provided.

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 respectively Heated Copper electrode A and Heated Copper electrode B.Described thermometric hybrid chamber A connects the first port of adaptor three-way A, and the 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 the first port of adaptor three-way B, and the 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, through adaptor three-way A, enters thermometric hybrid chamber A, and the bottom-up test section of flowing through, 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 insert respectively in thermometric hybrid chamber A and thermometric hybrid chamber B.

The thermocouple wire of described wall temperature thermopair evenly lays along the wall isotherm of developmental tube.Experimental provision based on above-mentioned, 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 inner diameter d, the length L of developmental tube _shortthe complete wall temperature thermopair of calibrating along 20 groups, every group 2 of pipe range direction uniform weldings, the Heated Copper electrode A that developmental tube import A place arranges of take is benchmark, the position of each wall temperature thermocouple welding point is measured, to determine that wall temperature thermopair is along the distribution situation of pipe range;

According to determining that until the viscosity of fluid measured this fluid is 600 to 1200 o'clock corresponding flow range of different temperatures at reynolds number Re number, to regulated the flow for the treatment of fluid measured in measuring process, experimentation should guarantee 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 working properly to guarantee it;

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, so that the import reynolds number Re of developmental tube reaches discreet value (800-1000).After temperature, pressure, flow are all stable, gather and record temperature, pressure and the flow value of fluid, be greater than 30s writing time, and image data is averaged to processing, after processing, obtain wall temperature and the fluid inlet and outlet temperature of total flow, each point.According to flow method thermal conductivity measurement formula:

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

Calculate the coefficient of heat conductivity for the treatment of fluid measured under this temperature case, wherein Q is the total amount of heat being added on tube wall, and L is test pipe range, and Δ T is defined as the poor of inside pipe wall temperature and fluid cross-section medial temperature, the mass rate that m is fluid, T _inwith T _outrespectively the temperature that fluid is imported and exported at developmental tube, Cp _aveaverage specific heat at constant pressure for fluid.

The 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 upper limit (20 ℃≤T≤600 ℃) of required measurement;

The 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 upper limit of required measurement, can obtain thus flow thermal conductivity coefficient variation with temperature relation under different pressures (0～7MPa).

The invention has the advantages that:

(1) adopt flow method to measure the coefficient of heat conductivity of fluid, and static experiment can only be measured the coefficient of heat conductivity of fluid under static condition, feature due to hydrocarbon fuel: under high temperature, irreversible variation can occur, all static measurement meetings cause the experimental data " distortion " on follow-up time point.And flow rule has effectively avoided occurring this situation;

(2) by effective adiabatic measure, effectively reduce heat transfer free convection thermal loss and radiation heat loss.

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

(4), than the transient state hot line measurement mechanism of traditional measurement flow thermal conductivity coefficient, that the new measurement based on this measuring method has is simple in structure, the Research and development and production cycle is short, to the outstanding advantages such as electromagnetic interference (EMI) is insensitive.Particularly importantly, adopt this measurement device flow thermal conductivity coefficient can greatly 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 the warm galvanic couple of developmental tube upper wall is arranged schematic diagram;

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 that is applicable to measure flow thermal conductivity coefficient provided by the invention is based on laminar flow, permanent hot-fluid border, flows and thermal boundary layer simultaneously under full-blown condition, the convection heat transfer of fluid in circular channel is mainly diffusion process, only relevant with flow thermal conductivity coefficient and caliber, therefore, the invention provides a kind of method and experimental provision that is 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.Theoretical derivation is as follows:

The momentum conservation equation of fluid is

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

According to full-blown velocity profile definition, obviously there is 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 is irrelevant with interior certain radius r a bit located of pipe, formula (2) can directly 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:

$u=\frac{{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="HDA0000454875140000011.png,HDA0000454875140000024.png"\; state="\{\{state\}\}">R</figure-callout>}}^2}{4\mathrm{\&mu;}}(-\frac{\mathrm{dp}}{\mathrm{dx}})(1-\frac{r^2}{R^2})---\left(4\right)$

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

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

Negligible axial heat conduction item again

can write:

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

Above formula (6) is the fundamental differential of inner tube layer stream.First, pipe is set up to cartesian coordinate system, u in above formula, v represent the speed component of x, y direction, the fluid component velocity of streamwise with perpendicular to the fluid component velocity of flow direction, a is thermal diffusivity, μ is kinetic viscosity, r is certain radius of a bit locating in pipe, 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 fluid density to be measured.

Boundary condition under permanent heat-flux conditions is:

r＝R,t＝t _w

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

Formula (7) substitution formula (6) can be obtained:

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

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

$t=t_w-\frac{2v}{a}\left(\frac{{\mathrm{dt}}_b}{\mathrm{dx}}\right)(\frac{{3\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="HDA0000454875140000011.png,HDA0000454875140000024.png"\; state="\{\{state\}\}">R</figure-callout>}}^2}{16}+\frac{1}{16}\frac{r^4}{R^2}-\frac{1}{4}{r}^2)---\left(9\right)$

Utilize the expression formula of medial temperature and average velocity 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 hot-fluid q on wall _wfor:

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

T in above formula _bfor fluid cross-section medial temperature, 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:

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

According to Newtonian Cooling formula, have:

$h=\frac{q}{\mathrm{\&Delta;T}}---\left(13\right)$

Heat flow density q is:

$q=\frac{Q}{\mathrm{\&pi;dL}}---\left(14\right)$

Wherein, d is bore (diameter).

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

$\mathrm{\&lambda;}=\frac{11\&CenterDot;Q}{48\&CenterDot;\mathrm{\&pi;}\&CenterDot;L\&CenterDot;\mathrm{\&Delta;T}}---\left(15\right)$

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

Q＝Cp _ave·m·(T _out-T _in) （16）

Therefore when permanent hot-fluid heats and meet 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）

Have:

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

So,

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

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 is accurately to obtain 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 wall temperature point is determined to slope (slope is oil temperature rate of curve) along pipe range and carry out linear regression to reduce stochastic error, draw the poor of intercept between wall temperature curve and fluid temperature (F.T.) curve, this difference is wall temperature-fluid temperature difference Δ T, by formula (15), can obtain the coefficient of heat conductivity of fluid under qualitative temperature.

Based on above-mentioned principle, the invention provides a kind of experimental provision that is 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 better developmental tube 1 to be incubated, also comprise screening heat shielding 13 and thermal insulation material 14 that developmental tube 1 outer wall is coated.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 respectively Heated Copper electrode A 2 and Heated Copper electrode B 3.Described thermometric hybrid chamber A4 connects the first port of adaptor three-way A11, and the 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 the first port of adaptor three-way B12, and the 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, through adaptor three-way A11, enters thermometric hybrid chamber A4, and the bottom-up developmental tube 1 of flowing through, through the thermometric hybrid chamber B5 in exit, is finally flowed out by outlet B.Described two Heated Copper electrode A 2 and B3 are connected power supply by the copper electrode A9 that goes between with copper electrode lead-in wire B10 respectively, and direct current supply voltage is provided.

Described developmental tube 1 is vertically placed, and adopts fluid mobile mode from the bottom up.For Measurement accuracy developmental tube 1 is imported and exported fluid temperature (F.T.), at developmental tube 1, import and export and weld respectively two fluid thermometric hybrid chamber A4 and thermometric hybrid chamber B5, in thermometric hybrid chamber A4 and thermometric hybrid chamber B5, installed respectively two-layer 200 object metal screens additional incoming flow is carried out to abundant blending.Described thermometric hybrid chamber A4 connects the first port of adaptor three-way A11, and the 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 the first port of adaptor three-way B12, and the 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, through adaptor three-way A11, enters thermometric hybrid chamber A4, and bottom-up 1 section of the developmental tube of flowing through, 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 are three sections of pipelines that internal diameter is different, internal diameter is respectively d1, d2 and d3, d1>d3>d2, inner diameter d 2 minimums of interlude, this section arranges metal screen, and described metal screen can be fixed on corresponding pipeline section.Internal diameter is that pipeline section and the corresponding adaptor three-way of d1 is welded and fixed, and pipeline section and developmental tube that internal diameter is d3 are welded and fixed.

Described fluid temperature (F.T.) thermopair A7 and fluid temperature (F.T.) thermopair B8 insert respectively in thermometric hybrid chamber A4 and thermometric hybrid chamber B5, and fluid temperature (F.T.) thermopair A7 and fluid temperature (F.T.) thermopair B8 are 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 wall surface temperature with the variation of pipe range, along 20 groups, every group 2 wall temperature thermopairs 6 of uniform welding on developmental tube 1, the thermocouple wire of wall temperature thermopair 6 lays along the wall isotherm of developmental tube 1, the concrete arrangement form of every group of two wall temperature thermopairs 6 as shown in Figure 3, the galvanic couple silk of two wall temperature thermopairs 6 is separately fixed at two relative points on the developmental tube 1 same circular section of outer wall, to reduce as far as possible wall temperature thermopair 6 temperature measurement errors.Every wall temperature thermopair 6 is all through calibrating, and gauging error is 0.1K.

Described experimental provision produces Joule heat and heats by directly add alternating voltage on developmental tube 1.Treat that fluid measured enters developmental tube 1 by developmental tube 1 low-temperature end import A, in described developmental tube 1 about 25mm place, two ends each fixed placement Heated Copper electrode A 2 and the Heated Copper electrode B 3 of distance, by stable dc power supply, powered, 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 flow out developmental tube 1 by temperature end outlet B.

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

It is 0.02W/(m*K that described thermal insulation material 14 adopts coefficient of heat conductivity) An Jiejia 5650 insulation materials.

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

Step 1: Measurement accuracy also records inner diameter d, the length L of developmental tube 1 _shortthe complete wall temperature thermopair 6 of calibrating along 20 groups, every group 2 of pipe range direction uniform weldings, the Heated Copper electrode A 2 that developmental tube 1 import A place arranges of take is benchmark, the position of each wall temperature thermopair 6 pad is measured, to determine that wall temperature thermopair 6 is along the distribution situation of pipe range;

Step 2: according to determining that until the viscosity of fluid measured this fluid is 600 to 1200 o'clock corresponding flow range of different temperatures at reynolds number Re number, to regulated the flow for the treatment of fluid measured in measuring process, experimentation should guarantee 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 working properly to guarantee it;

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, so that the import reynolds number Re of developmental tube 1 reaches discreet value (800-1000).After temperature, pressure, flow are all stable, gather and record temperature, pressure and the flow value of fluid, be greater than 30s writing time, and image data is averaged to processing, after processing, obtain the wall temperature T of flow m, each point _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 fluid inlet and outlet temperature, determine the curve that fluid temperature (F.T.) changes with pipe range, wall temperature is carried out determining the relational expression of slope one-variable linear regression to determine that wall temperature changes with pipe range according to fluid temperature (F.T.) slope of a curve.Poor wall-fluid temperature difference Δ the T that is of intercept of these two straight lines.According to flow method thermal conductivity measurement formula:

$\mathrm{\&lambda;}=\frac{11\&CenterDot;{\mathrm{Cp}}_{\mathrm{ave}}\&CenterDot;m\&CenterDot;(T_{\mathrm{out}}-T_{\mathrm{in}})}{48\mathrm{\&pi;}\&CenterDot;\mathrm{L\&Delta;T}}---\left(20\right)$

Calculate the coefficient of heat conductivity for the treatment of fluid measured under this temperature case, wherein, Cp _avefor fluid average specific heat at constant pressure holds, the mass rate that m is fluid, T _inand T _outfor fluid inlet and outlet temperature, L is test section pipe range, and Δ T is defined as the poor of inside pipe wall temperature and fluid cross-section medial temperature.

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

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

Adopt thermal conductivity measurement method provided by the invention and existing Transient Method to demarcating working medium toluene, to carry out coefficient of heat conductivity demarcation respectively, calibration result as shown in Figure 5, λ wherein _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 uniform temp and uniform pressure, while changing in the scope of Re number at 600-1200 in pipe, the thermal conductivity measurement error of fluid is all in ± 2% error band.

Claims (6)

1. an experimental provision that is applicable to flow model high-temperature, high pressure fluid Measured Results of Thermal Conductivity, is characterized in that: 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 respectively Heated Copper electrode A and Heated Copper electrode B; Described thermometric hybrid chamber A connects the first port of adaptor three-way A, and the 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 the first port of adaptor three-way B, and the 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, through adaptor three-way A, enters thermometric hybrid chamber A, and the bottom-up test section of flowing through, through the thermometric hybrid chamber B in exit, is finally flowed out by outlet B.

2. a kind of experimental provision that is applicable to flow model high-temperature, high pressure fluid Measured Results of Thermal Conductivity according to claim 1, is characterized in that: described fluid temperature (F.T.) thermopair A and fluid temperature (F.T.) thermopair B insert respectively in thermometric hybrid chamber A and thermometric hybrid chamber B.

3. a kind of experimental provision that is applicable to flow model high-temperature, high pressure fluid Measured Results of Thermal Conductivity according to claim 1, is characterized in that: the thermocouple wire of described wall temperature thermopair lays along the wall isotherm of developmental tube.

4. a kind of experimental provision that is applicable to flow model high-temperature, high pressure fluid Measured Results of Thermal Conductivity according to claim 1, is characterized in that: in thermometric hybrid chamber A and thermometric hybrid chamber B, installed respectively two-layer 200 object metal screens additional incoming flow is carried out to blending.

5. a kind of experimental provision that is applicable to flow model high-temperature, high pressure fluid Measured Results of Thermal Conductivity according to claim 1, is characterized in that: described screening heat shielding is aluminium glue band; It is 0.02W/(m*K that described thermal insulation material adopts coefficient of heat conductivity) insulation material.

6. an experimental technique that is applicable to flow model high-temperature, high pressure fluid Measured Results of Thermal Conductivity, 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, the complete wall temperature thermopair of calibrating along 20 groups, every group 2 of pipe range direction uniform weldings, the Heated Copper electrode A that developmental tube import A place arranges of take is benchmark, position to each wall temperature thermocouple welding point is measured, to determine that wall temperature thermopair is along the distribution situation of pipe range;

According to determining that until the viscosity of fluid measured this fluid is 600 to 1200 o'clock corresponding flow range of different temperatures at reynolds number Re number;

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 working properly to guarantee it;

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, so that the import reynolds number Re of developmental tube reaches discreet value 800-1000; After temperature, pressure, flow are all stable, gather and record temperature, pressure and the flow value of fluid, be greater than 30s writing time, according to flow method thermal conductivity measurement formula:

$\mathrm{\&lambda;}=\frac{11\&CenterDot;{\mathrm{Cp}}_{\mathrm{ave}}\&CenterDot;m\&CenterDot;(T_{\mathrm{out}}-T_{\mathrm{in}})}{48\mathrm{\&pi;}\&CenterDot;\mathrm{L\&Delta;T}}$

Calculate the coefficient of heat conductivity for the treatment of fluid measured under this temperature case, wherein, T _inwith T _outrespectively the temperature that fluid is imported and exported at developmental tube, Cp _avefor the average specific heat at constant pressure of fluid, L is test pipe range, and Δ T is the poor of inside pipe wall temperature and fluid cross-section medial temperature, the mass rate that m is fluid;

The 3rd step, changes developmental tube inlet temperature, repeats second step, carries out the measurement of the coefficient of heat conductivity of next temperature, and described temperature regulates within the scope of 20 ℃～600 ℃;

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

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