CN101887041B - Device and method for measuring thermal contact resistance under action of mechanical pressure - Google Patents

Abstract

The invention discloses a device and a method for measuring thermal contact resistance under the action of mechanical pressure. The method comprises the following steps of: measuring the temperature values of test points on a copper block, a first test piece (7I) and a second test piece (7II) by using an integrated data acquisition tester and a thermocouple, wherein the copper block, the first test piece (7I) and the second test piece (7II) are calibrated under the action of set pressure; carrying out linear regression to the temperature measured on each test piece and respectively outwards pushing the regression values to a contact interface to obtain the temperature values of the test pieces on the contact interface; subtracting the two temperature values on the contact interface to obtain the temperature drop of the contact interface; calculating two temperature values measured on the calibrated copper block according to the fundamental law of heat conduction to obtain the densities of thermal flows passing through the test pieces; and then acquiring the thermal contact resistance of the first test piece (7I) and the second test piece (7II) under the action of the set mechanical pressure according to the calculating formula of the thermal contact resistance.

Description

Thermal contact resistance under action of mechanical pressure measurement mechanism and measuring method

Technical field

The present invention relates to a kind of the pressurization and heating condition under thermal contact resistance measurement mechanism and measuring method, can be used for fields such as power-thermal coupling experiment, thermal protection technology, LASER HEATING.

Background technology

Cross when type of thermal communication and to cause thermal contact resistance when being in contact with one another the surface, the direct contact that its essence is solid surface and solid surface can only occur on some discrete points or the small area, because the coefficient of heat conductivity and the solid conductive heat coefficient of gap dielectric generally differ greatly between the surface, thereby hot-fluid changes near causing surface of contact, form the additional drag of hot-fluid, the phenomenon that this contact interface causes thermal transient under action of mechanical pressure is conducted the field (as the thermal protection of spacecraft, Laser Processing, laser weapon etc.) be complicated, the relation of thermal contact resistance and its influence factor is non-linear, needs to measure.Fields such as power-thermal coupling engineering, thermal protection, LASER HEATING need the experimental provision of thermal contact resistance under action of mechanical pressure.

Summary of the invention

The purpose of this invention is to provide a kind of thermal contact resistance under action of mechanical pressure measurement mechanism and measuring method.Described thermal contact resistance under action of mechanical pressure measurement mechanism is positioned in the pressing machine 10, thermal contact resistance under action of mechanical pressure measurement mechanism periphery is provided with drum type brake heat insulation layer 2, heat insulation layer 2 is placed on 2 shock absorption buffering mechanism II, place the first test specimen 7I and the second test specimen 7II in the heat insulation layer 2, the first test specimen 7I top is placed with heating arrangement I, the second test specimen 7II is placed in the tank 4, shock absorption buffering mechanism II is across on the tank 4, at the first test specimen 7I and the second test specimen 7II shaft a plurality of temperature thermocouples 1 are set, thermopair 1 is connected to the integrated form number and adopts tester 5 (it is UXI-10016/50016 that general survey control Science and Technology Ltd. model is opened up in Sichuan), and the integrated form number is adopted tester 5, pressing machine 10 is connected with computer 6.

Described heating arrangement I comprises copper billet 8, steel disc 9, asbestos layer 11 and the resistance wire 12 of demarcation, be placed with resistance wire 12 in the groove of the copper billet of demarcating 8, be placed with steel disc 9 on the copper billet of demarcating 8, place asbestos layer 11 on the steel disc 9, the copper billet 8 of demarcation is provided with two temperature thermocouples 1.

The described first test specimen 7I, the second test specimen 7II and heat insulation layer 2 are provided with the aperture of relevant position, and two apertures also are set on the copper billet 8 of demarcation, and thermometric thermocouple 1 is passed on copper billet 8, the first test specimen 7I and the second test specimen 7II that heat insulation layer 2 is inserted in demarcation respectively.

Described shock absorption buffering mechanism II is two, is separately positioned on heat insulation layer 2 both sides along tank 4 directions, and shock absorption buffering mechanism II comprises spring 3, support 13 and sleeve 14, and spring 3 is arranged in the sleeve 14, and support 13 is enclosed within outside the sleeve 14.

Measuring method of the present invention is:

The integrated form number is adopted tester 5, pressing machine 10 is connected with computer 6, transmits and show the working pressure of the temperature and pressure machine 10 of test specimen (7I, 7II) test point respectively.The first test specimen 7I and the second test specimen 7II are packed in the heat insulation layer 2, carry out precompressed with the 10 couples first test specimen 7I of pressing machine and the second test specimen 7II, make the output pressure of pressing machine 10 keep setting value then, flow through the water of room temperature in the tank 4, adopt 220V voltage, resistance wire (12) heating power, adopt tester 5 with the integrated form number and measure the copper billet of demarcating 8 Deng reaching thermally-stabilised back, the first test specimen 7I and the second test specimen 7II go up the temperature value of test point, to on the first test specimen 7I and the second test specimen 7II, the temperature of measured each point carry out linear regression, be known certain function some discrete function values f1, f2 ... fn}, by adjust some undetermined coefficient f in this function (λ 1, and λ 2 ... λ 3), make difference (least square method) minimum of this function and known point set.If function undetermined is linear, just cry linear fit or linear regression, obtain equation of linear regression then.Regressand value is extrapolated to the contact interface place of the first test specimen 7I and the second test specimen 7II respectively, the contact interface place that is about to the first test specimen 7I and the second test specimen 7II brings equation of linear regression into to the distance of setting initial point, obtain the first test specimen 7I and the second test specimen 7II temperature value, two temperature values at contact interface place are subtracted each other the temperature drop that obtains the contact interface place at the contact interface place; Then by 2 measured temperature on the copper billet of demarcating 8, try to achieve heat flow density according to the heat conduction philosophy by the first test specimen 7I and the second test specimen 7II, at last according to the thermal contact resistance computing formula, try to achieve the thermal contact resistance of the first test specimen 7I and the second test specimen 7II.By the variation of some parameters, can test the funtcional relationship that obtains pressure thermal contact resistance under action influence factor.

The advantage that the present invention is compared with prior art had:

The present invention is intended to propose the thermal contact resistance under action of mechanical pressure measurement mechanism, simple and making easily, and measured result is also quite accurate, is convenient to education experiment and scientific research.

Description of drawings

Fig. 1 is the synoptic diagram of thermal contact resistance under action of mechanical pressure measurement mechanism;

Fig. 2 is the synoptic diagram of resistive heater;

Fig. 3 is the A direction visual angle synoptic diagram of Fig. 1;

Fig. 4 is a cross-sectional side view;

Fig. 5 be of the present invention under embodiment two conditions the hyperboloid fitted figure of experimental data.

Among the figure: 1 is the thermometric thermocouple, and 2 is heat insulation layer, and 3 is spring, 4 is tank, and 5 adopt tester for the integrated form number, and 6 is computer, 7I is first test specimen, and 7II is second test specimen, 8 copper billets for demarcation, 9 is steel disc, and 10 is pressing machine, and 11 is asbestos layer, 12 is resistance wire, and 13 is support, and 14 is sleeve, 15 mica sheets, I are heating arrangement, and II is a shock absorption buffering mechanism.

Embodiment

The invention provides a kind of thermal contact resistance under action of mechanical pressure measurement mechanism and measuring method.Contrast accompanying drawing below, illustrate and realize embodiments of the invention:

Embodiment one (as shown in Figure 1)

The integrated form number is adopted tester 5, pressing machine 10 is connected with computer 6, transmits respectively and shows working pressure on the temperature and pressure machine 10 of test specimen (7I, 7II) test point; The first test specimen 7I and the second test specimen 7I I are packed in the heat insulation layer 2, carry out precompressed with the 10 couples first test specimen 7I of pressing machine and the second test specimen 7II, make the output pressure of pressing machine 10 keep setting value then, flow through the water of room temperature in the tank 4, adopt 220V voltage, resistance wire (12) heating power, reach heat transmit stable after, adopt tester 5 with the integrated form number and measure the copper billet of demarcating 8, the first test specimen 7I and the second test specimen 7II go up the temperature value of test point, and will on the first test specimen 7I and the second test specimen 7II, the temperature of measured each point carry out linear regression, regressand value is extrapolated to the contact interface place of the first test specimen 7I and the second test specimen 7II respectively, obtain the first test specimen 7I and the second test specimen 7II temperature value, two temperature values at contact interface place are subtracted each other the temperature drop that obtains the contact interface place at the contact interface place; Then by 2 measured temperature on the copper billet of demarcating 8, try to achieve heat flow density according to the heat conduction philosophy by the first test specimen 7I and the second test specimen 7II, at last according to the thermal contact resistance computing formula, try to achieve the thermal contact resistance between the first test specimen 7I and the second test specimen 7II under the set pressure effect.

Respectively get 4 points on two test specimens (length is h), measuring number of times is 1 time, is example with the first test specimen 7I, and establishing each point on the test specimen is y to the distance of the first test specimen 7I upper end _i, measured each point temperature is T _i, be listed as follows:

y	y 1	y 2	y 3	y 4
					T	T 1	T 2	T 3	T 4
ω	1	1	1	1

According to the thermal conduction characteristic of homogeneous material, can suppose that equation form is S ₁(y)=a ₀+ a ₁Y,

According to the least square method formula of curve fitting, promptly

So

Get by formula (1)

$\left\{\begin{array}{c}{4a}_0+\underset{i=0}{\overset{3}{\mathrm{\Σ}}}{y}_i{a}_1=\underset{i=0}{\overset{3}{\mathrm{\Σ}}}{T}_i\\ \underset{i=0}{\overset{3}{\mathrm{\Σ}}}{y}_i{a}_0+\underset{i=0}{\overset{3}{\mathrm{\Σ}}}{y}_i^2{a}_1=\underset{i=0}{\overset{3}{\mathrm{\Σ}}}{y}_i{T}_i\end{array}\right.---\left(2\right)$

Derive by following formula:

$a_0=\frac{\underset{i=0}{\overset{3}{\mathrm{\Σ}}}{y}_i\×\underset{i=0}{\overset{3}{\mathrm{\Σ}}}{y}_i{T}_i-\underset{i=0}{\overset{3}{\mathrm{\Σ}}}{y}_i^2\×\underset{i=0}{\overset{3}{\mathrm{\Σ}}}{T}_i}{{\left(\underset{i=0}{\overset{3}{\mathrm{\Σ}}}{y}_i\right)}^2-4\underset{i=0}{\overset{3}{\mathrm{\Σ}}}{y}_i^2}$

${\mathrm{<figure-callout\; id="1"\; label="a"\; filenames="HSA00000180259100011.png"\; state="\{\{state\}\}">a</figure-callout>}}_1=\frac{\underset{i=0}{\overset{3}{\mathrm{\&Sigma;}}}{T}_i\&times;\underset{i=0}{\overset{3}{\mathrm{\&Sigma;}}}{y}_i-4\underset{i=0}{\overset{3}{\mathrm{\&Sigma;}}}{y}_i{T}_i}{{\left(\underset{i=0}{\overset{3}{\mathrm{\&Sigma;}}}{y}_i\right)}^2-4\underset{i=0}{\overset{3}{\mathrm{\&Sigma;}}}{y}_i^2}---\left(3\right)$

Again by S ₁(y)=a ₀+ a ₁Y can get

$T_s\left(y_s\right)=S_1\left(y_s\right)=\frac{\underset{i=0}{\overset{3}{\mathrm{\&Sigma;}}}{y}_i\&times;\underset{i=0}{\overset{3}{\mathrm{\&Sigma;}}}{y}_i{T}_i-\underset{i=0}{\overset{3}{\mathrm{\&Sigma;}}}{y}_i^2\&times;\underset{i=0}{\overset{3}{\mathrm{\&Sigma;}}}{T}_i}{{\left(\underset{i=0}{\overset{3}{\mathrm{\&Sigma;}}}{y}_i\right)}^2-4\underset{i=0}{\overset{3}{\mathrm{\&Sigma;}}}{y}_i^2}+\frac{\underset{i=0}{\overset{3}{\mathrm{\&Sigma;}}}{T}_i\&times;\underset{i=0}{\overset{3}{\mathrm{\&Sigma;}}}{y}_i-4\underset{i=0}{\overset{3}{\mathrm{\&Sigma;}}}{y}_i{T}_i}{{\left(\underset{i=0}{\overset{3}{\mathrm{\&Sigma;}}}{y}_i\right)}^2-4\underset{i=0}{\overset{3}{\mathrm{\&Sigma;}}}{y}_i^2}{y}_s$

In like manner can get

$T_x\left(y_x\right)=\frac{\underset{j=0}{\overset{3}{\mathrm{\&Sigma;}}}{y}_j\&times;\underset{j=0}{\overset{3}{\mathrm{\&Sigma;}}}{y}_j{T}_j-\underset{j=0}{\overset{3}{\mathrm{\&Sigma;}}}{y}_j^2\&times;\underset{j=0}{\overset{3}{\mathrm{\&Sigma;}}}{T}_j}{{\left(\underset{i=0}{\overset{3}{\mathrm{\&Sigma;}}}{y}_j\right)}^2-4\underset{j=0}{\overset{3}{\mathrm{\&Sigma;}}}{y}_j^2}+\frac{\underset{j=0}{\overset{3}{\mathrm{\&Sigma;}}}{T}_j\&times;\underset{j=0}{\overset{3}{\mathrm{\&Sigma;}}}{y}_j-4\underset{j=0}{\overset{3}{\mathrm{\&Sigma;}}}{y}_j{T}_j}{{\left(\underset{i=0}{\overset{3}{\mathrm{\&Sigma;}}}{y}_j\right)}^2-4\underset{i=0}{\overset{3}{\mathrm{\&Sigma;}}}{y}_j^2}{y}_x$

Above-mentioned two formulas of coordinate h substitution can get T at the interface _s(h), T _x(h), the temperature difference T that tries to achieve thus at the interface is,

ΔT＝T _s(h)-T _x(h) (4)

Be respectively Tcu1 and Tcu2 by two temperature values on the measured copper billet of temperature thermocouple again,

ΔT _CU＝T _CU1-T _CU2 (5)

The heat conduction philosophy is arranged, vertically led prismatic heat flow density as can be known:

$\stackrel{\&RightArrow;}{q}=-\mathrm{\&lambda;}\frac{\mathrm{\&Delta;T}}{\mathrm{\&Delta;x}}\stackrel{\&RightArrow;}{n}---\left(6\right)$

Negative sign represents that heat flow density is opposite with the direction of thermograde in the formula,

Be the normal direction unit vector on this isotherm, point to the direction that temperature raises, be the heat flow density vector, λ is a thermal conductivity, Be the thermograde of object along the x direction, i.e. rate of temperature change.

Get by above-mentioned heat conduction philosophy:

$q={\mathrm{\&lambda;}}_{\mathrm{cu}}\frac{\mathrm{\&Delta;}{T}_{\mathrm{CU}}}{\mathrm{\&Delta;L}}---\left(7\right)$

Q is the heat flow density by test specimen in the formula, and λ cu is the demarcation coefficient of heat conductivity of copper billet, and Δ L is the distance of two points for measuring temperature of copper billet.

At last according to the thermal contact resistance computing formula:

$R=\frac{\mathrm{\&Delta;T}}{q}---\left(8\right)$

Draw thermal contact resistance R.

In addition, according to the heat conduction philosophy, also can record the temperature conductivity of test specimen:

${\mathrm{\&lambda;}}_{7I}=\frac{q\&times;\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HSA00000180259100011.png"\; state="\{\{state\}\}">L</figure-callout>}}_1}{\mathrm{\&Delta;}{T}_a}---\left(9\right)$

${\mathrm{\&lambda;}}_{7\mathrm{II}}=\frac{q\&times;\mathrm{\&Delta;}{L}_2}{\mathrm{\&Delta;}{T}_b}---\left(10\right)$

Δ L in the formula ₁Be last two distances of facing mutually between the point for measuring temperature of the first test specimen 7I, Δ T _aBe that two of the first test specimen 7I face temperature difference between the point for measuring temperature mutually; Δ L ₂Be last two distances of facing mutually between the point for measuring temperature of the second test specimen 7II, Δ T _bBe two temperature differences of facing mutually between the point for measuring temperature of the second test specimen 7II.

Embodiment two (as shown in Figure 5)

Be with embodiment one difference: this example control material for test one test specimen surface roughness Ra of making peace keeps certain value, the temperature value T of change pressure P (the pressure setting range is decided according to material mechanical performance) that pressing machine provided and the test specimen surface each point of getting, then by calculating the thermal contact resistance R under each pressure P and the temperature value T, draw equation R=f (q by match, P), draw thermal contact resistance R, pressure P and the triangular three-dimensional relationship of hot-fluid q under the material for test condition consistent by tabulation at last with the test specimen surface roughness Ra.

Embodiment three

Be with embodiment one and embodiment two differences: this example control material for test one pressure P of making peace keeps certain value, change the temperature value T of the test specimen surface each point of getting and the roughness Ra on test specimen surface, then by calculating the thermal contact resistance R under each temperature value T and the roughness Ra, draw equation R=f (Ra by match, P), draw in material for test one pressure P of making peace by tabulation at last and keep thermal contact resistance R, hot-fluid q and the triangular three-dimensional relationship of roughness Ra under the condition of definite value.

Embodiment four

Be with embodiment one, embodiment two and embodiment three differences: this example makes two, and material for test is inconsistent and maintenance test specimen surface roughness Ra is constant, the temperature value T of change pressure P that pressing machine provided and the new test specimen surface each point of getting, then by calculating the thermal contact resistance R under each pressure P and the temperature value T, draw equation R=f (q by match, P), draw thermal contact resistance R, pressure P and the triangular three-dimensional relationship of hot-fluid q under new material for test one is made peace the constant condition of test specimen surface roughness Ra by tabulation at last.

Embodiment five

Be with embodiment one, embodiment two, embodiment three and embodiment four differences: this example makes material for test inconsistent constant with the P that keep-ups pressure, change the temperature value T of the new test specimen surface each point of getting and the roughness Ra on new test specimen surface, then by calculating the thermal contact resistance R under each temperature value T and the roughness Ra, draw equation R=f (Ra by match, P), draw in new material for test one pressure P of making peace by tabulation at last and keep thermal contact resistance R, hot-fluid q and the triangular three-dimensional relationship of roughness Ra under the condition of definite value.

Claims (4)

1. thermal contact resistance under action of mechanical pressure measurement mechanism, it is characterized in that, described thermal contact resistance under action of mechanical pressure measurement mechanism is positioned in the pressing machine (10), the skin of this thermal contact resistance measurement mechanism is provided with a drum type brake heat insulation layer (2), heat insulation layer (2) is placed on two shock absorption buffering mechanisms (II), place first test specimen (7I) and second test specimen (7II) in the heat insulation layer (2), first test specimen (7I) top is placed with heating arrangement (I), the part that second test specimen (7II) exposes heat insulation layer (2) is placed in the tank (4), shock absorption buffering mechanism (II) is across on the tank (4), on first test specimen (7I) and second test specimen (7II) shaft, a plurality of temperature thermocouples (1) are set, thermopair (1) is connected to the integrated form number and adopts tester (5), and the integrated form number is adopted tester (5), pressing machine (10) is connected with computer (6); Described heating arrangement (I) comprises copper billet (8), steel disc (9), asbestos layer (11), resistance wire (12) and the mica sheet (15) of demarcation; Order is placed with mica sheet (15) and resistance wire (12) in the groove of the copper billet of demarcating (8), be placed with steel disc (9) on the copper billet of demarcating (8), steel disc (9) is gone up and is placed asbestos layer (11), the copper billet of demarcating (8) is provided with two temperature thermocouples (1), and these two temperature thermocouples (1) are connected to the integrated form number equally and adopt tester (5).

2. a kind of thermal contact resistance under action of mechanical pressure measurement mechanism according to claim 1, it is characterized in that, the aperture of relevant position is set on described first test specimen (7I), second test specimen (7II) and the heat insulation layer (2), temperature thermocouple (1) passes heat insulation layer (2) and is inserted on first test specimen (7I) and second test specimen (7II), and two apertures also are set on the copper billet of demarcation (8).

3. a kind of thermal contact resistance under action of mechanical pressure measurement mechanism according to claim 1, it is characterized in that, described shock absorption buffering mechanism (II) is two, be separately positioned on heat insulation layer (2) both sides along tank (4) direction, shock absorption buffering mechanism (II) comprises spring (3), support (13) and sleeve (14), spring (3) is arranged in the sleeve (14), and support (13) is enclosed within outside the sleeve (14), and contacts with spring (3).

4. one kind is used the described measurement mechanism of claim 1 to carry out the thermal contact resistance under action of mechanical pressure measuring method, it is characterized in that described measuring method is:

The integrated form number is adopted tester (5) and is connected with computer (6) with pressing machine (10), transmits respectively and shows working pressure on the temperature and pressure machine (10) of test specimen (7I, 7II) test point; Second test specimen (7II) and first test specimen (7I) order is packed in the heat insulation layer (2), with pressing machine (10) first test specimen (7I) and second test specimen (7II) are carried out precompressed, make the output pressure of pressing machine (10) keep setting value then, the pressure setting range is decided according to material mechanical performance, flow through the water of room temperature in the tank (4), adopt 220V voltage, resistance wire (12) heating power, reach heat transmit stable after, adopt tester (5) with the integrated form number and measure the copper billet of demarcating (8), first test specimen (7I) and second test specimen (7II) are gone up the temperature value of test point, and will on first test specimen (7I) and second test specimen (7II), the temperature of measured each point carry out linear regression, regressand value is extrapolated to the contact interface place of first test specimen (7I) and second test specimen (7II) respectively, obtain first test specimen (7I) and second test specimen (7II) temperature value, two temperature values at contact interface place are subtracted each other the temperature drop that obtains the contact interface place at the contact interface place; Go up 2 measured temperature by the copper billet of demarcating (8) then, try to achieve heat flow density according to the heat conduction philosophy by first test specimen (7I) and second test specimen (7II), at last according to the thermal contact resistance computing formula, try to achieve the thermal contact resistance between first test specimen (7I) and second test specimen (7II) under the set pressure effect.

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