CN101126729A - Double heat flux gauge steady state method for measuring material heat conductivity - Google Patents

Abstract

The utility model relates to a material thermal conductivity measuring method of double heat-flux meter steady-state method, belonging to the technical field of material heat conduction performance testing. Based on the analysis of one-dimensional heat conduction in multilayer flat plate, the utility model proposes the adoption of the method of double heat-flux meter and samples with different thickness for heat conduction measurement, and gives quantitative criterion of one-dimensional heat conduction. The utility model adopts multi-point temperature measurement in heat-flux meter, calculates the average heat flux density with one-dimensional heat conduction formula of multi-layer flat plate, overcomes the difficulty of inaccurate heat flux density measurement, and makes alignment-fitting calculation for the actual thermal conductivity coefficient and the interface thermal resistance with test data of samples with different thickness. In addition, the utility model can test not only the thermal conductivity of solid material, but also the thermal conductivity coefficient of film material.

Description

Double heat flux gauge steady state method for measuring material heat conductivity

Technical field

The invention belongs to material thermal conductivity energy technical field of measurement and test, particularly relate to the thermal conductivity test of Micro-electronics Plastic Sealing material.

Background technology

The heat conduction behavior of material is all paid close attention in thermal power, metallurgy, chemical industry, electronics, building and Aero-Space and bioengineering field widely, for example, heating and ventilation in the electronic devices and components in electronic technology and the cooling of electronic equipment, the construction work, the temperature control in chemical engineering etc. all need to know the heat conductivility of material, promptly need the coefficient of heat conductivity of test material.

At present material thermal conductivity can method of testing has two kinds of steady state method and Instantaneous Method.Specifically derive a lot of method of testings again according to different physical models.The stable state flat band method is to measure the classical way of the coefficient of heat conductivity of insulation material, has that sample production is convenient, principle is clear, can accurately, directly obtain advantages such as coefficient of heat conductivity absolute value, and be suitable for wide temperature range, thereby be widely used.Yet classical steady state method exists, and Measuring Time is long, hot-fluid is difficult to problems such as accurately test, is difficult to accurately realize steady-state process.The unstable state mensuration is the thermal conductivity measurement method of developing in nearest decades, is used for studying the high thermal conductivity coefficient material more, or measures under hot conditions.In the transient state method, the Temperature Distribution of sample changes in time during measurement, generally calculates coefficient of heat conductivity by measuring this variation of temperature.The characteristics of dynamic method are that Measuring Time is short, accuracy is high, low to environmental requirement, but be subjected to the restriction of measuring method, be used for the measurement that specific heat is tending towards the middle and high warm area coefficient of heat conductivity of constant substantially more.

Chinese patent 93115076.0 has been narrated a kind of experimental provision that utilizes steady state method test material heat conductivility, this method in the specimen side coated with the heating plate of known area and known power as thermal source, heating plate is carried out insulation to realize one-dimensional stable heat conduction, the sample another side is coated with the dish that is heated, by measuring heating plate and the temperature of the dish that is heated, try to achieve the thermal conductivity of specimen according to the Fourier heat-conduction equation.This method proving installation is simple, convenient test.But this method is accepted heat with whole known power of thermal source as specimen, and disposal route is too rough, does not consider the thermal loss of thermal insulation material.This method is not considered heating plate in addition and the thermal resistance of be heated dish and sample contact interface, can make the temperature difference that records heating plate and be heated between the dish become big so again.Chinese patent 86101542 has been narrated a kind of method that adopts two sample measurement solid material high temperature heat conductivilitys, be characterized in being positioned at middle primary heater of two samples and ring-shaped heater as thermal source, type of thermal communication is crossed sample, soaking plate, heat insulation layer, scatter and disappear by the water-cooled cold drawing at last, measure the temperature difference of two sample upper and lower surfaces respectively, substitution Fourier heat-conduction equation calculates the coefficient of heat conductivity of trying to achieve material.Though this method adopts the water-cooled cold drawing to strengthen the one dimension transmission of hot-fluid, but still be to adopt the heat flux of the heating power metering of well heater by specimen, do not consider the thermal loss of sample side, do not consider well heater soaking plate and specimen interface resistance simultaneously yet.

Chinese invention patent application 200310112520.3 and 200410015458.0 has been narrated respectively and adopted novel aluminium oxide/carbon nano tube compound material is the method for the measurement material thermal conductivity energy of adiabatic apparatus, it has adopted thermal source, first heat flow meter, testing sample, second heat flow meter, cryotron to arrange in order and has made its test structure that fits tightly mutually, i.e. " sandwich " type sample structure.The core of this method is to adopt the alumina composite material that contains the oriented alignment carbon nano-tube as adiabatic apparatus, has improved the heat-insulating property of proving installation.The derby metering of the known thermal conductivity by being positioned at the sample both sides is by the heat flow density of specimen, and determine the thermograde of sample both sides by the temperature of measuring diverse location in the derby, calculate the thermal conductivity that obtains detected materials by the Fourier formula at last.Yet this method suppose that proving installation realized one-dimensional stable heat conduction when the heat flow density of calculating by sample, equal fully with the heat flow density of the derby that is positioned at the sample upper and lower surface by sample.By measuring the thermograde of a certain section in the known coefficient of heat conductivity derby, utilize the Fourier formula to calculate the heat flux that obtains by sample like this.Above-mentioned hypothesis has been ignored the hot-fluid loss of sample side and the thermal contact resistance between sample and the derby, because the coefficient of heat conductivity of copper is bigger, the thermograde of adjacent position test is less in the copper derby, and the therefore measured heat flow density of passing through sample exists than mistake.In addition, in this method, the conduction of hot-fluid one dimension also lacks quantitative criteria, and the coefficient of heat conductivity test result is not the coefficient of heat conductivity of sample itself for to comprise the effective thermal conductivity of interface resistance at interior sample yet.

Summary of the invention

The objective of the invention is to overcome the deficiency of existing steady state method test material heat conductivility, a kind of measuring method more accurately is provided.

A kind of double heat flux gauge steady state method for measuring material heat conductivity may further comprise the steps:

(1), thermal source, first heat flow meter, testing sample, second heat flow meter, cryotron are arranged in order and it is fitted tightly mutually;

(2), utilize heat-barrier material to fit tightly thermal source, cryotron inboard, and around first heat flow meter, testing sample, second heat flow meter, make the sequence delivery of heat according to step (1);

(3), at first heat flow meter, second heat flow meter 3-6 temperature sensing point is set respectively; It is characterized in that this method is further comprising the steps of:

(4), according to temperature sensing point measurement data, utilize the Fourier formula $Q=\frac{\mathrm{\ΔT}}{\mathrm{\Δx}}\mathrm{\λ},$ Calculate evenly heat flow q respectively by first heat flow meter _{Heat flow meter 1}, by the evenly heat flow q of second heat flow meter _{Heat flow meter 2}, and calculate the overall average heat flux q that passes through first heat flow meter and second heat flow meter, wherein

(5), the heat flux that flows through first heat flow meter and second heat flow meter in conduction process satisfies

During this condition, then think, can carry out material thermal conductivity according to the following steps and measure near realizing one-dimensional stable heat conduction;

(6), utilize formula $\frac{\mathrm{\ΔT}}{q}=\frac{\mathrm{\Δx}}{{\mathrm{\λ}}_{\mathrm{true}}}+\frac{m}{h}$ Calculate material thermal conductivity, wherein Δ T falls for considering that the contact bed temperature is fallen at interior sample total moisture content, and Δ x is that sample thickness is known through measuring, λ _TrueBe the true thermal conductivity of sample to be asked, m is that the number of system's median surface layer is known, and h is the thermal conductance of contact bed;

(7), in the formula of step (6) because Δ T/q is the function of Δ x, slope and intercept are respectively 1/ λ _TrueAnd m/h, therefore utilize the hot-fluid test of same material different-thickness sample to make the function curve of Δ T/q and Δ x, according to the slope of the function curve of Δ T/q and Δ x and the λ that intercept is determined sample _TrueAnd h, wherein q calculates by step (4), and Δ x is known through measuring, and m is known, and Δ T obtains by the linear match of multi-point temperature measurement temperature.

Above-mentioned first heat flow meter and the metering of second hot-fluid can be adopted the 304 stainless steel metal right cylinders of two Φ 30 * 40mm, and each stainless steel cylinder is provided with four temperature points for measuring temperature on fixed intervals 10mm position; Specimen is of a size of: diameter is that 30mm, thickness are the disk shape sample of the different-thickness of 1～5mm;

Above-mentioned double heat flux gauge steady state method for measuring material heat conductivity, being specially adapted in test thermal conductance scope is the room temperature coefficient of heat conductivity of the solid material of 1～10W/mK.Especially Micro-electronics Plastic Sealing material is such as the epoxy mold material.

The present invention is analyzing on the heat conducting basis of multi-layer planar wall one dimension, proposes to adopt two heat flow meters and different-thickness sample to carry out the method that heat conduction is measured, and provides the heat conducting quantitative criteria of one dimension.Adopt multi-point temperature measurement in the heat flow meter, utilize multi-layer planar wall one dimension heat conduction formula to calculate and obtain mean heat flux, overcome heat flow density and measured inaccurate difficulty, and utilized different-thickness sample test data to carry out true thermal conductivity and interface thermal conductance that linear The Fitting Calculation obtains material.In addition, the present invention not only can test the coefficient of heat conductivity of solid material, and thermal conductivity coefficient that can the MEASUREMENTS OF THIN material.

Description of drawings

The two heat flow meter steady state method thermal conductivity test structural representations of Fig. 1.

(m=2) passed the thermograde synoptic diagram of heat flow meter and sample when Fig. 2 had two interfaces.

Fig. 3 experimental provision synoptic diagram.

The relation curve of Fig. 4 quartz glass specimen Δ T/q and Δ x data.

The temperature gradient curve of overheated flowmeter of Fig. 5 type of thermal communication and different-thickness quartz glass samples.

The relation curve of Fig. 6 polystyrene specimen Δ T/q and Δ x data.

The temperature gradient curve of overheated flowmeter of Fig. 7 type of thermal communication and different-thickness polystyrene sample.

The relation curve of Figure 84 5 steel specimen Δ T/q and Δ x data.

The temperature gradient curve of overheated flowmeter of Fig. 9 type of thermal communication and different-thickness 45 steel samples.

Number in the figure title: 1-first heat flow meter, 2-specimen, 3-temperature gradient curve, 4-second heat flow meter, 5-well heater, 6-water-cooled box, 7-bolt hold down gag, 8-temperature test and data acquisition.

Embodiment

One, below in conjunction with accompanying drawing the computing formula derivation that in particular, the present invention relates to is elaborated:

According to the heat flow density computing formula of multi-layer planar one-dimensional stable heat conduction, select for use two heat flow meters and sample to constitute " sandwich " multi-layer planar structure.The transmission direction of control hot-fluid realizes the one-dimensional stable heat conduction pattern of multi-layer planar, in each heat flow meter, equidistantly choose several temperature measurement point (hypothesis is chosen 4 in the following derivation), measure the thermograde of the overheated flowmeter of type of thermal communication, in view of the above the heat flow density of the overheated flowmeter of measurement flow.Two heat flow meter structural representations as shown in Figure 1.

In Fig. 1, represent with q by first heat flow meter with by the heat flux of second heat flow meter.T ₁-T ₈Be the temperature acquisition points of eight temperature sensors in heat flow meter, x ₁-x ₈Be the distance of each collection point to sample.

In shown in Figure 2 pair of heat flow meter structure, Δ T is that total temperature is fallen, and Δ x is a sample thickness, and h is the thermal conductance (supposing that two interface thermal conductances equate) of contact bed, and i and c refer to interface and sample respectively.

In Fig. 3, sample is in the middle of two heat flow meters, and the side skin is an insulating sleeve, and internal layer is the PS polyfoam, and skin is the PVC plastic tube.

In an embodiment, the Δ T/q of Fig. 4, Fig. 6 and Fig. 8 and the relation curve of Δ x are different-thickness sample test result's matched curve, can determine the coefficient of heat conductivity and the interface thermal conductance of sample by matched curve; When Fig. 5, Fig. 7 and Fig. 9 reached stable state for this proving installation, the temperature gradient curve of overheated flowmeter of type of thermal communication and different-thickness specimen can calculate the temperature difference Δ T that determines the sample upper and lower surface by this temperature gradient curve.

For first heat flow meter, establishing coefficient of heat conductivity is λ ₁, the temperature of each measurement point is T ₁, T ₂, T ₃, T ₄, each measurement point is x apart from the distance of sample ₁, x ₂, x ₃, x ₄, then the heat flow density by different measuring point position is respectively q ₁, q ₂, q ₃, q ₄, q ₅, q ₆:

${\mathrm{<figure-callout\; id="1"\; label="q"\; filenames="A20071013264700171.png,A20071013264700181.png"\; state="\{\{state\}\}">q</figure-callout>}}_1=\frac{T_2-T_1}{x_2-x_1}{\mathrm{\&lambda;}}_1---\left(1\right)$

${\mathrm{<figure-callout\; id="2"\; label="q"\; filenames="A20071013264700171.png,A20071013264700181.png"\; state="\{\{state\}\}">q</figure-callout>}}_2=\frac{T_3-T_2}{x_3-x_2}{\mathrm{\&lambda;}}_1---\left(2\right)$

${\mathrm{<figure-callout\; id="3"\; label="q"\; filenames="A20071013264700171.png,A20071013264700181.png"\; state="\{\{state\}\}">q</figure-callout>}}_3=\frac{T_3-T_1}{x_3-x_1}{\mathrm{\&lambda;}}_1---\left(3\right)$

${\mathrm{<figure-callout\; id="4"\; label="q"\; filenames="A20071013264700171.png,A20071013264700181.png"\; state="\{\{state\}\}">q</figure-callout>}}_4=\frac{T_4-T_1}{x_4-x_1}{\mathrm{\&lambda;}}_1---\left(4\right)$

${\mathrm{<figure-callout\; id="5"\; label="q"\; filenames="A20071013264700181.png,A20071013264700201.png"\; state="\{\{state\}\}">q</figure-callout>}}_5=\frac{T_4-T_2}{x_4-x_2}{\mathrm{\&lambda;}}_1---\left(5\right)$

${\mathrm{<figure-callout\; id="6"\; label="q"\; filenames="A20071013264700181.png,A20071013264700201.png"\; state="\{\{state\}\}">q</figure-callout>}}_6=\frac{T_4-T_3}{x_4-x_3}{\mathrm{\&lambda;}}_1---\left(6\right)$

Under one-dimensional stable heat conduction situation, should equate that by each temperature survey point position heat flow density in the heat flow meter therefore, the total mean heat flux of first heat flow meter is

That is:

In like manner, the expression formula that can obtain by the mean heat flux in second heat flow meter is:

$T_{\mathrm{ave}}^{\mathrm{jk}}=\frac{T_j+T_k}{2}---\left(10\right)$

Here j, k refers to thermocouple location, λ ₁(T _Ave ^Jk) and λ ₂(T _Ave ^Jk) be respectively first heat flow meter and second heat flow meter at T _Ave ^JkThermal conductivity during temperature.So the evenly heat flow by first heat flow meter and second heat flow meter can be written as:

When the heat flux that flows through first heat flow meter and second heat flow meter in the conduction process satisfies following condition, think that the author is referred to as one-dimensional stable heat conduction coefficient of determination near realizing one-dimensional stable heat conduction:

When the derivation above-mentioned relation, suppose that each dull and stereotyped side fits tightly, so surface of contact both sides temperature is identical.But the total surface of two contacts is rough and uneven in surface under actual conditions, is difficult to reach fit tightly.Such surface contact situation will exist additional thermal resistance in conduction process, be called thermal contact resistance.Figure 2 shows that the thermograde synoptic diagram that passes heat flow meter and sample under the steady state conditions.Suppose and do not consider the side thermal loss, then the hot-fluid by sample and its contact bed equates, so:

$q={\mathrm{\&lambda;}}_{\mathrm{eff}}\frac{\mathrm{\&Delta;T}}{\mathrm{\&Delta;x}}---\left(13\right)$

q＝hΔT _i (14)

$q={\mathrm{\&lambda;}}_{\mathrm{true}}\frac{\mathrm{\&Delta;}{T}_c}{\mathrm{\&Delta;x}}---\left(15\right)$

Here λ _EffBe the available heat conductance of sample, Δ T is that total temperature is fallen, and Δ x is a sample thickness, and h is the thermal conductance (supposing that two interface thermal conductances equate) of contact bed, λ _TrueBe the true thermal conductivity of sample, i and c refer to interface and sample respectively.

In the test, total temperature is fallen Δ T and is meant the temperature drop that passes sample and interface:

ΔT＝ΔT _c+mΔT _j (16)

Here m is the number of system's median surface layer, with formula (14), formula (15) substitution formula (16), can obtain:

$\frac{\mathrm{\&Delta;T}}{q}=\frac{\mathrm{\&Delta;x}}{{\mathrm{\&lambda;}}_{\mathrm{true}}}+\frac{m}{h}---\left(17\right)$

By formula (17) as can be known Δ T/q be the function of Δ x, slope and intercept are respectively 1/ λ _TrueAnd m/h.λ _TrueCan map with h the sample testing data of different-thickness (adopt same material) obtain.

Make the function curve of Δ T/q and Δ x according to the hot-fluid test of different-thickness sample.According to the slope of the function curve of Δ T/q and Δ x and the coefficient of heat conductivity that intercept is determined sample.In order to reduce side hot-fluid loss, the employing thickness of heat flow meter and sample side carries out thermal protection for the 20mm polystyrene foam, and outermost layer adopts the PVC plastic tube to seal.

Two, below in conjunction with accompanying drawing device and method of the present invention is described further:

1, Fig. 3 is this principle of device synoptic diagram, and it comprises:

(1). a temperature programmed control heating arrangement 5.The board-like heating arrangement of employing temperature programmed control heats " sandwich " structure of two heat flow meters and sample formation, and heating power is stable, and can set the heating maximum temperature.There is thermopair to carry out temperature control between thermal source and the heat transfer copper coin, gives first heat flow meter 4 heating by the heat transfer copper coin;

(2). two heat flow meters.Adopt the heat flow meter of two 304 moderate stainless steel metal right cylinders of thermal conductivity as the hot-fluid metering.Sample 2 is coated heat-conducting silicone grease at the interface between two heat flow meters 1,4, reduce interface resistance.The inherent fixed intervals (10mm) of each heat flow meter are provided with four temperature point for measuring temperature (T on the position ₁To T ₈, Pt100 type thermistor, 0.1 ℃ of sensitivity), measure the formed thermograde of hot-fluid of passing through stainless steel cylinder heat flow meter when reaching stable state.

(3). two-layer thermal protection sleeve 9,10.The side of heat flow meter and sample side adopt thickness be the polystyrene foamed material 9 of 20mm as thermofin, outermost layer also adopts PVC plastic tube 10 to entangle, and plays the effect of thermal protection for the second time, is convenient to the arrangement of temperature probe simultaneously.

(4). a cooling device 6.Water-circulating cooling device 6 is installed in the top, compresses through pressurization bolt 7, guarantees that with the heating arrangement acting in conjunction heat input and transfer rate keep constant.In addition, set up and force the cooling heat dissipation effect, help the foundation of thermograde in " sandwich " structure measurement device, improve the accuracy of test.

(5). a test monitor system 8.Utilize multiple spot scan tester XMD-2000A (0.1 ℃ of measuring accuracy) 7 collecting temperature readings, and be transferred to the supervisory system monitoring of adopting autonomous establishment on the computer.Not only can monitor the temperature value of eight temperature acquisition points, and can observe the curvilinear motion situation that temperature raises in each temperature test point heating process.Usually, after heating a period of time, temperature variation in 10 minutes ± 0.5 ℃ think that with interior conduction reaches one-dimensional stable.

(6). data are handled the software for calculation system.Eight temperature data values of gathering are imported in the testing software of independent developments, obtained the ratio of sample upper and lower surface temperature gap and upper and lower base plate mean heat flux.Repeatedly measure the sample of different-thickness, repeat above-mentioned steps, obtain experimental data, the test data of different-thickness sample is carried out linear match obtain straight slope, utilize formula $\frac{\mathrm{\&Delta;T}}{q}=\frac{\mathrm{\&Delta;x}}{{\mathrm{\&lambda;}}_{\mathrm{true}}}+\frac{m}{h}$ Calculate the material temperature conductivity, wherein Δ T falls for considering that the contact bed temperature is fallen at interior sample total moisture content, and Δ x is that sample thickness is known through measuring, λ _TrueBe the true thermal conductivity of sample to be asked, m is that the number of system's median surface layer is known, and h is the thermal conductance of contact bed; Obtain the true coefficient of heat conductivity of specimen thus.

2, method of testing of the present invention comprises the following steps:

(1). check whether computer supervisory control system is connected with the data line of multi-point data acquisition instrument 8 intact, whether inspection heat hot origin system 5 contacts intact with thermopair between the heat transfer copper coin, and whether water pump, the water pipe of inspection cold water device 6 be intact.

(2). determine above-mentioned all right after, can connect computing machine, multi-point data acquisition instrument 8 power supplys.And open monitoring software on the computing machine, check whether complete transmission of (8) eight temperature input signals of multi-point data acquisition instrument.As passage T ₁～T ₈In temperature when in ± 0.5 ℃, fluctuating, it is normal to illustrate that instrument connects, and can test.

(3). coat the layer of even heat-conducting silicone grease in heat transfer copper coin (diameter 35mm) center, then first heat flow meter (4) (304 stainless steel) is positioned over the copper coin center, connect, well contacted by heat-conducting silicone grease.

(4). utilize milscale that the testing sample 2 of polishing is carried out thickness measure three times, be averaged numerical value, obtain thickness of sample Δ x.Then, coat heat-conducting silicone grease at specimen surface.Can use hairbrush, small blade as aid.Attention wipes out because of the not careful a small amount of silicone grease that is coated in the sample side of operation gently with sponge or soft cloth.After coating, (diameter 30mm) is placed on the upper surface of first heat flow meter (4) with sample 2, the centering adjustment position.Add the auxiliary protection insulation sleeve of sample gently.Entangle sample from top to bottom, note the not position of mobile sample.

(5). on sample, add second heat flow meter (1) then, notice that the centering adjustment place pushes down sample.Left hand is by living in matrix, and the right hand is fetched cooling water system (copper dish) and is placed on the matrix top and pushes down.Left hand does not unclamp, and the right hand applies suitable pressure hold down gag by pressurization bolt (7).At this moment, check whether thermocouple jack becomes flexible.If have looseningly, be inserted into inner end again, otherwise accurate collecting temperature data.

(6). connect the cooling device power supply, current begin to circulate.Connect the heat hot origin system, the design temperature parameter; Open supervisory system, setting signal collection period (suggestion was got 10 seconds), newly-built test record just can be tested.

(7). repeatedly measure the sample of different-thickness, repeat above-mentioned steps, obtain testing straight line, and then obtain straight slope, obtain the true thermal conductivity of specimen thus.

In experimental provision, adopt the heat flow meter of the 304 stainless steel metal right cylinders of two Φ 30 * 40mm as the hot-fluid metering, the thermal conductivity of 304 stainless steels when 333K is 14.92W/mK.Each stainless steel cylinder is provided with four temperature points for measuring temperature on fixed intervals (10mm) position, Pt100 type thermistor (0.1 ℃ of temperature control) is measured the formed thermograde of hot-fluid of passing through stainless steel cylinder heat flow meter when reaching stable state.Diameter is that the disk shape sample of 30mm, different-thickness is put into the test of carrying out heat conduction heat flux between two heat flow meters, makes the function curve of Δ T/q and Δ x according to the hot-fluid test of different-thickness sample.According to the slope of the function curve of Δ T/q and Δ x and the coefficient of heat conductivity that intercept is determined sample.In order to reduce side hot-fluid loss, the employing thickness of heat flow meter and sample side carries out thermal protection for the 20mm polystyrene foam, and outermost layer adopts the PVC plastic tube to seal.

Adopt programme controlled board-like heating arrangement that " sandwich " structure of two heat flow meters and sample formation is heated, type of thermal communication is crossed heating arrangement and is passed to stainless steel cylinder heat flow meter and sample.Type of thermal communication is crossed first heat flow meter and sample when being positioned at second heat flow meter transmission of top, is producing thermograde in two stainless steel cylinder heat flow meters up and down respectively.For the one dimension of further strengthening hot-fluid flows, on stainless steel cylinder second heat flow meter, place water-circulating cooling device, realize the one dimension conduction mode.Simultaneously, keep stable, require thermal source and flow of cooling water speed must keep constant for guaranteeing the heat delivered process.In addition, in order to reduce the influence of interface resistance to the heat conductivility test, coat heat-conducting silicone grease at the interface at stainless steel cylinder heat flow meter and sample two, whole measuring system adopts bolt to compress, and further improves measuring accuracy and repeatability.

Utilize the multi-point temp detector to gather Pt100 thermistor (0.1 ℃ of sensitivity) and measure temperature reading (T ₁To T ₈), and will measure temperature data and be transferred on the computing machine, adopt temperature sensor measurement variation of temperature on the supervisory system monitoring heat flow meter fixed position of autonomous establishment.When each measurement point temperature variation in 10 minutes in ± 0.5 ℃, can think that conduction reaches one-dimensional stable.At last, with the Data Processing in Experiment software of eight temperature data values input independent developments of gathering, just can calculate the coefficient of heat conductivity of sample.

Three,, effect of the present invention is described further below in conjunction with embodiment:

This contrive equipment adopts novel pair of heat flow meter steady state method, measures the material thermal conductivity energy based on multi-layer planar one-dimensional stable conduction principle, can effectively overcome the heat flow measurement that exists in the steady state method heat conductivity measuring device in the past inaccurate wait not enough.Utilize standard sample transparency silica glass, 45 steel and the polystyrene of known hot physical data that device is tested, it is fine that the coefficient of heat conductivity numerical value of acquisition and document recommendation meet.The experimental provision of being invented can record (1Wm in the certain limit exactly ^-1K ^-1＜λ＜10Wm ^-1K ^-1) coefficient of heat conductivity of solid sample, good reproducibility can satisfy the needs of actual construction material thermal conductivity measurement, and can study the electric substrate material thermal conductivity provides a kind of important means.Utilize Visual C++6.0 language development to go out to run on full-automatic testing and data processing software under the Windows XP environment simultaneously, improved the automaticity device of coefficient of heat conductivity test, simple to operate.

Embodiment one:

With the known one group of quartz glass samples of coefficient of heat conductivity, adopt the heat conductivility of heat conductivility proving installation specimen of the present invention.Test result sees Table 1.Sample upper and lower surface keeping parallelism and warp are careful to be ground and polishing, is coated with heat-conducting silicone grease the minimizing interface resistance simultaneously respectively in the sample upper and lower surface.Specimen is put into up and down between the two-layer heat flow meter template, by the pressurization bolt at instrument top exert pressure (generally being not more than 0.7MPa).

Table 1 specimen and test result

The sample title	Thickness/mm	ΔT/q (Km 2kW -1)	One dimension heat conduction coefficient of determination	Temperature conductivity/Wm -1K -1	Bibliographical information temperature conductivity test value/Wm -1K -1
						Quartz glass	1.168	1.114	9.4％	1.47	1.42
2.260	1.696	5.2％
			3.070	2.472	3.6％
4.180	2.884	1.0％
			5.080	3.469	7.1％
6.178	4.69	2.1％
			Polystyrene (PS)	2.015	11.989		29.9％	0.22	0.15～0.20
3.282	17.770	34.4％
				4.262	22.775	64.1％
5.743	28.362	68.1％
				45 steel	1.940	0.041	8.7％.			41.7	47.68
3.001	0.065	3.7％
			4.998		0.114	6.5％
7.180	0.166	7.9％

Figure 4 shows that the relation curve of quartz glass specimen Δ T/q and Δ x data, the coefficient of heat conductivity of being tried to achieve quartz glass by slope of a curve among the figure is 1.47Wm ^-1K ^-1, with bibliographical information test data 1.42Wm ^-1K ^-1Compare, it is fine that experiment test value and bibliographical information value are coincide.Fig. 5 when reaching stable state for this proving installation, the temperature gradient curve of overheated flowmeter of type of thermal communication and different-thickness specimen.As seen from the figure, be arranged in sample first heat flow meter and the temperature T that records of the point for measuring temperature of second heat flow meter up and down ₁-T ₄And T ₅-T ₈Curve is near parallel, and the slope of two straight lines is equal substantially.The heat flow density of explanation in first heat flow meter and second heat flow meter is equal substantially, can think that experimental provision realized one-dimensional stable heat conduction pattern in test under the working condition.

Embodiment two:

With the known one group of polystyrene sample of coefficient of heat conductivity, adopt the heat conductivility of heat conductivility proving installation specimen of the present invention.Test result sees Table 1.Figure 6 shows that the relation curve of polystyrene specimen Δ T/q and Δ x data, the coefficient of heat conductivity of being tried to achieve polystyrene by slope of a curve among the figure is 0.22Wm ^-1K ^-1, with bibliographical information test data 0.15～0.20Wm ^-1K ^-1Compare, it is also fine that experiment test value and bibliographical information value are coincide.Fig. 7 when reaching stable state for this proving installation, the temperature gradient curve of the specimen of overheated flowmeter of type of thermal communication and different-thickness.

Embodiment three:

With known one group of carbon containing, the 0.45% plain carbon steel sample of coefficient of heat conductivity, adopt the heat conductivility of heat conductivility proving installation specimen of the present invention.Test result sees Table 1.Figure 8 shows that the relation curve of 45 steel specimen Δ T/q and Δ x data, the coefficient of heat conductivity of being tried to achieve 45 steel by slope of a curve among the figure is 41.7Wm ^-1K ^-1, with bibliographical information test data 47.68Wm ^-1K ^-1Compare, it is also fine that experiment test value and bibliographical information value are coincide.Fig. 7 when reaching stable state for this proving installation, the temperature gradient curve of the specimen of overheated flowmeter of type of thermal communication and different-thickness.

Only the above, it only is a preferred embodiment of the present invention, be not to be used for limiting scope of the invention process, the equalization of doing according to the described shape of the present patent application claim, structure, feature and spirit changes and modifies in every case, all should be included in the claim of the present invention.

Claims (5)

1. double heat flux gauge steady state method for measuring material heat conductivity may further comprise the steps:

(1), thermal source, first heat flow meter, testing sample, second heat flow meter, cryotron are arranged in order and it is fitted tightly mutually;

(2), utilize heat-barrier material to fit tightly thermal source, cryotron inboard, and around first heat flow meter, testing sample, second heat flow meter, make the sequence delivery of heat according to step (1);

(3), at first heat flow meter, second heat flow meter 3-6 temperature sensing point is set respectively;

It is characterized in that this method is further comprising the steps of:

(4), according to temperature sensing point measurement data, utilize the Fourier formula $Q=\frac{\mathrm{\&Delta;T}}{\mathrm{\&Delta;x}}\mathrm{\&lambda;},$ Calculate evenly heat flow q respectively by first heat flow meter _{Heat flow meter 1}, by the evenly heat flow q of second heat flow meter _{Heat flow meter 2}, and calculate the overall average heat flux q that passes through first heat flow meter and second heat flow meter, wherein

(5), the heat flux that flows through first heat flow meter and second heat flow meter in conduction process satisfies

During this condition, then think, can carry out material thermal conductivity according to the following steps and measure near realizing one-dimensional stable heat conduction;

(6), utilize formula $\frac{\mathrm{\&Delta;T}}{q}=\frac{\mathrm{\&Delta;x}}{{\mathrm{\&lambda;}}_{\mathrm{true}}}+\frac{m}{h}$ Calculate material thermal conductivity, wherein Δ T falls for considering that the contact bed temperature is fallen at interior sample total moisture content, and Δ x is that sample thickness is known through measuring, λ _TrueFor sample to be asked true

Real thermal conductivity, m is that the number of system's median surface layer is known, h is the thermal conductance of contact bed;

(7), in the formula of step (6) because Δ T/q is the function of Δ x, slope and intercept are respectively l/ λ _TrueAnd m/h, therefore utilize the hot-fluid test of same material different-thickness sample to make the function curve of Δ T/q and Δ x, according to the slope of the function curve of Δ T/q and Δ x and the λ that intercept is determined sample _TrueAnd h, wherein q calculates by step (4), and Δ x is known through measuring, and m is known, and Δ T obtains by the linear match of multi-point temperature measurement temperature.

2. according to the described double heat flux gauge steady state method for measuring material heat conductivity of claim 1, it is characterized in that: the 304 stainless steel metal right cylinders of two Φ 30 * 40mm are adopted in described first heat flow meter and the metering of second hot-fluid, and each stainless steel cylinder is provided with four temperature points for measuring temperature on fixed intervals 10mm position; Specimen is of a size of: diameter is that 30mm, thickness are the disk shape sample of the different-thickness of 1～5mm.

3. according to claim 1 or 2 described double heat flux gauge steady state method for measuring material heat conductivity, it is characterized in that: this method is applied to test the room temperature coefficient of heat conductivity that the thermal conductance scope is the solid material of 1～10W/mK.

4. according to the described double heat flux gauge steady state method for measuring material heat conductivity of claim 3, it is characterized in that: described solid material refers to the Micro-electronics Plastic Sealing material.

5. according to the described double heat flux gauge steady state method for measuring material heat conductivity of claim 4, it is characterized in that: the epoxy resin-based ceramic particle reinforcing material of described Micro-electronics Plastic Sealing material finger ring.

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