CN105044149A - Method for measuring heat conductivity of heat insulation material under different water contents - Google Patents
Method for measuring heat conductivity of heat insulation material under different water contents Download PDFInfo
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- CN105044149A CN105044149A CN201510466290.3A CN201510466290A CN105044149A CN 105044149 A CN105044149 A CN 105044149A CN 201510466290 A CN201510466290 A CN 201510466290A CN 105044149 A CN105044149 A CN 105044149A
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Abstract
The invention discloses a method for measuring the heat conductivity of a heat insulation material under different water contents. The method includes the steps that two identical samples are taken and dried to be absolute dry, one sample serves as a calibration sample, and the other sample serves as a sample to be measured; the sample to be measured is subjected to water absorption treatment to have a needed water content w; the heat conductivity of the calibration sample is measured through a steady state method under the mean temperature T, and a test result is recorded as lambda2; a non-steady state method is calibrated through the calibration sample and the test result lambda2 under the mean temperature T; the sample, obtained after water absorption treatment, to be measured is tested through the calibrated non-steady state method under the mean temperature T, the heat conductivity lambda (w, T) of the sample to be measured under the water content w and the mean temperature T is obtained, and measurement is completed. By means of the method for measuring the heat conductivity of the heat insulation material under the different water contents, water can be effectively restrained from migrating in the samples or dispersing outwards, and therefore it is guaranteed that the water content in the samples is uniform in measurement. The method has the advantages of being simple, high in accuracy and the like.
Description
Technical field
The present invention relates to a kind of method measuring thermal insulation material coefficient of heat conductivity under different water cut condition.
Background technology
The heat conductivility of thermal insulation material is one of key parameter determining its product quality, therefore in quality testing process for the Accurate Determining of material thermal conductivity by extremely important.In the concerned countries standard of existing thermal insulation material Measured Results of Thermal Conductivity, as GB/T10294, GB/T10295, only pay close attention to the impact of temperature factor for material thermal conductivity, and ignore the impact of material moisture content on coefficient of heat conductivity.But in actual use, thermal insulation material is subject to the impact of the nature such as weather, construction or non-natural factor, himself can contain a certain amount of moisture, and how many meetings of contained humidity cause which kind of change of material conducts heat performance, there is no unified calibration steps at present and accurately weigh.Therefore, be necessary to set up a kind of suitable method of testing, for assessment of the size of thermal insulation material coefficient of heat conductivity under different water cut condition.
Summary of the invention
The invention provides a kind of method measuring thermal insulation material coefficient of heat conductivity under different water cut condition, can the coefficient of heat conductivity of Measurement accuracy material under different water cut, simple to operate, accuracy is high.
For solving the problems of the technologies described above, the technical solution adopted in the present invention is as follows:
Measure a method for thermal insulation material coefficient of heat conductivity under different water cut condition, comprise the steps:
1) get two samples to same sample and be dried to over dry, wherein one as calibration sample, and another is as treating test sample;
2) will treat that test sample does water suction process, to required water percentage w;
3) in medial temperature be T condition under, with the coefficient of heat conductivity of steady state method Measurement and calibration sample, and test result is designated as λ 2;
4) in medial temperature be T condition under, calibrate the experimental apparatus of cold store enclosure with calibration sample and test result λ 2;
5) in medial temperature be T condition under, with calibration after cold store enclosure experimental apparatus test water suction after treat test sample, must until test sample water percentage be w, medial temperature be T time coefficient of heat conductivity λ (w, T), complete measurement.
Applicant finds after deliberation, uses steady state method heat conducting coefficient measuring, consuming time long, if to the testing of materials containing certain moisture, then there is water translocation and distribute problem, thus the accuracy that impact is measured, therefore, steady state method is suitable for the Measurement accuracy of over dry material thermal conductivity; And cold store enclosure, although test speed is fast, accuracy is relatively low; Applicant after deliberation, cold store enclosure is calibrated with steady state method, thus utilize the cold store enclosure after calibration accurately to record the coefficient of heat conductivity of material under certain water percentage, can be good at limiting moisture migration in the sample and distributing outwardly, the homogeneity of sample inner aqueous when ensureing to measure, improves the accuracy measured and simple to operate.
Above-mentioned steps 1) in the quantity of sampling quantity of two samples determine as the case may be, in order to improve accuracy further, often kind is desirable multiple, then averages.
In order to improve the accuracy of measurement further, step 1) in, get two samples there is identical size.
Conveniently measure, ensure simultaneously measure accuracy, step 1) in, get the tabular that two samples are surfacing.
In order to improve the accuracy of measurement further, prevent sample from absorbing or distributing moisture, preferably, step 2) in, will treat that test sample moisture-inhibiting resistance is at least the diaphragm seal of 200MNs/g after water suction process, and place the uniform moisture distribution making to treat in test sample; Further preferably, step 2) in, to treat that test sample hinders the diaphragm seal being at least 200MNs/g with two-layer above moisture-inhibiting after water suction process, but the gross thickness of film used must not exceed treats 1/100 of test sample original thickness, and place more than 96h, every 22-26h, standing sample is overturn 180 ° between resting period, make the uniform moisture distribution treated in test sample.
Above-mentionedly treat that the original thickness of test sample refers to the thickness before being dried to over dry.
In order to improve the accuracy of measurement further, preferably, step 1) in, the calibration sample moisture-inhibiting resistance being dried to over dry is at least the diaphragm seal of 200MNs/g.Further preferably, step 1) in, the calibration sample being dried to over dry is hindered with two-layer above moisture-inhibiting the diaphragm seal being at least 200MNs/g, but the gross thickness of film used must not exceed 1/100 of calibration sample original thickness.
The original thickness of above-mentioned calibration sample refers to the thickness before being dried to over dry.
The choosing of film meets moisture-inhibiting resistance and is at least 200MNs/g, but in order to ensure the sealing effectiveness to sample, thus improve the accuracy of measurement, preferably, film is the polyethylene film that thickness is not less than 0.1mm.
In order to improve the accuracy of measurement further, preferably, step 4) in, calibration steps is: regulate calibration factor according to the comparison between measurement of instability value and steady state measurement value λ 2, until the continuous coefficient of heat conductivity deviation recording calibration sample for more than 3 times of measurement of instability method is no more than 0.001W/ (mK), can think that verification is qualified.
Conveniently measure, ensure the accuracy measured, step 3 simultaneously) in, steady state method is with reference to the method in GB/T10294 or GB/T10295; Step 4) in, cold store enclosure is heat-pole method (with reference to GB/T10297) or plane heat source method (with reference to GB/T10297, ISO22007-2).
Further preferably, a kind of method measuring thermal insulation material coefficient of heat conductivity under different water cut condition, comprises the steps:
1) to same sample, get the sample that two have same size, respectively called after sample 1 and sample 2, at the temperature of correlation standard, be dried to over dry, weigh immediately, the quality now taking sample 1 and sample 2 is respectively m
1and m
2;
2) full leaching mode is adopted by sample 1 to put into the container filling water, carry out water suction process, period can carry out regularly or irregularly weighing to this sample, after reaching the aqueous conditions needed for test, rapid taking-up, within 1min, remove surperficial water droplet with thieving paper is quickly dipped soon, take sample 1 quality m now immediately
1 *, obtain the wet basis water percentage of sample 1:
Wrap up at sample 1 surface uniform the film that two-layer moisture-inhibiting resistance is at least 200MNs/g immediately to seal, in laboratory environment, place more than 96h, standing sample is overturn 180 ° every 24h by period, to ensure moisture being uniformly distributed in sample inside;
3) for the sample 2 after oven dry, same its surface uniform wrapped up the film that two-layer moisture-inhibiting resistance is at least 200MNs/g and seal, according to the method in GB/T10294 or GB/T10295, be under the condition of T in medial temperature, the sample coefficient of heat conductivity of absolute dry condition is measured, and test result is designated as λ
2;
4) by the coefficient of heat conductivity λ of sample 2
2as standard value, be adopt the coefficient of heat conductivity of cold store enclosure to sample 2 to measure in the constant temperature enclosure (case) of T in temperature, period regulates calibration factor according to the comparison between measured value and standard value, until the continuous coefficient of heat conductivity deviation recording sample 2 for 5 times is no more than 0.001W/ (mK), can think that instrument verification is qualified;
5) after cold store enclosure instrument has verified, rapidly by step 2) sample 1 of gained, be adopt cold store enclosure to carry out thermal conductivity measurement in the constant temperature enclosure (case) of T in temperature, can obtain sample 1 water percentage be w, medial temperature be T time coefficient of heat conductivity λ (w, T), so far tested.
Above-mentioned steps 3)-5) in test time, the film at sample and instrument probe localized contact point place need be removed, to protect fully contacting of positive sample and probe.
The NM technology of the present invention is all with reference to prior art.
The present invention measures the method for thermal insulation material coefficient of heat conductivity under different water cut condition and compensate for the deficiency of classic method when measuring thermal insulation material coefficient of heat conductivity under different water cut condition, can be good at limiting moisture migration in the sample and distributing outwardly, the homogeneity of sample inner aqueous when ensureing to measure, have that method of testing is simple, accuracy advantages of higher, the new method of thermal insulation material Measured Results of Thermal Conductivity under different water cut condition can be become.
Embodiment
In order to understand the present invention better, illustrate content of the present invention further below in conjunction with embodiment, but content of the present invention is not only confined to the following examples.
Embodiment 1
The measurement of moisture rock cotton board coefficient of heat conductivity, comprises the following steps that order connects:
(1) first, to rock cotton board goods, get two block length 300 ± 2mm, width 300 ± 2mm, thickness is the plate tensile sample of the former thick surfacing of sample, called after sample 1 and sample 2 respectively, weigh immediately be dried to constant weight in the baking oven of 105 DEG C after, the sample 1 now taken and the quality of sample 2 are respectively m
1=695.58g and m
2=698.15g.
(2) full leaching mode is adopted by sample 1 to put into the container filling certain water yield, carry out water suction process, period, every 24h weighed sample mass, after reaching the aqueous conditions needed for test, rapid taking-up, within 1min, remove surperficial water droplet with thieving paper is quickly dipped soon, take sample 1 quality m now immediately
1 *=1256.65g, obtains the wet basis water percentage of sample 1:
(3) immediately at sample 1 surface uniform parcel two layers of polyethylene film (thickness in monolayer is 0.1mm), at the Laboratory air (23 ± 1 DEG C of standard; 50% ± 10%RH) middle placement 7d, standing sample is overturn 180 ° every 24h by period, to ensure moisture being uniformly distributed in sample inside.
(4) for the sample 2 after oven dry, equally by its surface uniform parcel two layers of polyethylene film (thickness in monolayer is 0.1mm), adopt heat flow meter method (with reference to GB/T10295), be under the condition of 25 DEG C in medial temperature, the rock wool sample coefficient of heat conductivity recording absolute dry condition is λ
2=0.038W/ (mK).
(5) by the coefficient of heat conductivity λ of sample 2
2as standard value, be in the constant temperature enclosure of 25 DEG C, adopt heat-pole method (with reference to GB/T10297) to measure the coefficient of heat conductivity of sample 2 in temperature, period regulates calibration factor according to the comparison between measured value and standard value, the continuous heat conduction recording sample 2 for 5 times is 0.038W/ (mK), meets instrument and verifies qualified condition.
(6) after instrumental calibration completes, rapidly by sample 1, be adopt heat-pole method to carry out thermal conductivity measurement in the constant temperature enclosure of 25 DEG C in temperature, obtaining this sample at water percentage is 44.65%, coefficient of heat conductivity λ (44.65% when medial temperature is 25 DEG C, 25)=0.199W/ (mK), test completes.
When testing in above steps, the film at sample and instrument probe localized contact point place need be removed, to protect fully contacting of positive sample and probe.
For verifying the accuracy of the inventive method, the rock wool sample to be measured that 3 have same size is got again from same sample, and they are cultured to identical water percentage, above step (1)-(6) are adopted to carry out parallel testing, each sample all tests 3 times, amount to 9 experimental results, be respectively: 0.199W/ (mK), 0.201W/ (mK), 0.198W/ (mK), 0.202W/ (mK), 0.201W/ (mK), 0.197W/ (mK), 0.199W/ (mK), 0.199W/ (mK), 0.201W/ (mK), their relative standard deviation is less than 1%, can find out that test findings has good repeatability, this also illustrates the accuracy of the inventive method.
Claims (10)
1. measure a method for thermal insulation material coefficient of heat conductivity under different water cut condition, it is characterized in that: comprise the steps:
1) get two samples to same sample and be dried to over dry, wherein one as calibration sample, and another is as treating test sample;
2) will treat that test sample does water suction process, to required water percentage w;
3) in medial temperature be T condition under, with the coefficient of heat conductivity of steady state method Measurement and calibration sample, and test result is designated as λ 2;
4) in medial temperature be T condition under, calibrate the experimental apparatus of cold store enclosure with calibration sample and test result λ 2;
5) in medial temperature be T condition under, with calibration after cold store enclosure experimental apparatus test water suction after treat test sample, must until test sample water percentage be w, medial temperature be T time coefficient of heat conductivity λ (w, T), complete measurement.
2. the method for claim 1, is characterized in that: step 1) in, get two samples there is identical size.
3. method as claimed in claim 2, is characterized in that: step 1) in, get the tabular that two samples are surfacing.
4. the method as described in claim 1-3 any one, is characterized in that: step 2) in, will treat that test sample moisture-inhibiting resistance is at least the diaphragm seal of 200MNs/g after water suction process, and place the internal moisture treating test sample is uniformly distributed.
5. method as claimed in claim 4, it is characterized in that: step 2) in, to treat that test sample hinders the diaphragm seal being at least 200MNs/g with two-layer above moisture-inhibiting after water suction process, but the gross thickness of film used must not exceed treats 1/100 of test sample original thickness, and place more than 96h, every 22-26h, standing sample is overturn 180 ° between resting period, the internal moisture treating test sample is uniformly distributed.
6. method as claimed in claim 4, is characterized in that: step 1) in, the calibration sample moisture-inhibiting resistance being dried to over dry is at least the diaphragm seal of 200MNs/g.
7. method as claimed in claim 6, is characterized in that: step 1) in, the calibration sample being dried to over dry is hindered with two-layer above moisture-inhibiting the diaphragm seal being at least 200MNs/g, but the gross thickness of film used must not exceed 1/100 of calibration sample original thickness.
8. method as claimed in claim 6, is characterized in that: film is the polyethylene film that thickness is not less than 0.1mm.
9. the method as described in claim 1-3 any one, it is characterized in that: step 4) in, calibration steps is: regulate calibration factor according to the comparison between measurement of instability value and steady state measurement value λ 2, until the continuous coefficient of heat conductivity deviation recording calibration sample for more than 3 times of measurement of instability method is no more than 0.001W/ (mK), can think that verification is qualified.
10. the method as described in claim 1-3 any one, is characterized in that: step 3) in, steady state method is with reference to the method in GB/T10294 or GB/T10295; Step 4) in, cold store enclosure is heat-pole method or plane heat source method.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110361416A (en) * | 2019-05-31 | 2019-10-22 | 惠州学院 | A kind of measurement method of the sucting wet state thermal coefficient of moisture-absorbing fibre textile material |
| CN113176294A (en) * | 2021-04-27 | 2021-07-27 | 内蒙合成化工研究所 | Calibration method of heat conductivity coefficient tester by protective heat flow meter method |
| CN114675013A (en) * | 2022-04-02 | 2022-06-28 | 中国林业科学研究院木材工业研究所 | Method and equipment for determining wood drying shrinkage/wet swelling behavior |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110361416A (en) * | 2019-05-31 | 2019-10-22 | 惠州学院 | A kind of measurement method of the sucting wet state thermal coefficient of moisture-absorbing fibre textile material |
| CN110361416B (en) * | 2019-05-31 | 2022-02-18 | 惠州学院 | Method for measuring heat conductivity coefficient of moisture-absorption fiber fabric material in moisture-absorption state |
| CN113176294A (en) * | 2021-04-27 | 2021-07-27 | 内蒙合成化工研究所 | Calibration method of heat conductivity coefficient tester by protective heat flow meter method |
| CN114675013A (en) * | 2022-04-02 | 2022-06-28 | 中国林业科学研究院木材工业研究所 | Method and equipment for determining wood drying shrinkage/wet swelling behavior |
| CN114675013B (en) * | 2022-04-02 | 2024-05-28 | 中国林业科学研究院木材工业研究所 | Method and equipment for measuring dry shrinkage/wet expansion behavior of wood |
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