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Lijia Tips: [Cold and Heat Shock Test Chamber] Elements of Correct Selection

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Release date: 2019-06-08

1,The cold and hot shock test chamber is a smooth channel occupied by the test components after entering the chamber. Narrowing the channel will lead to an increase in flow rate and accelerate the air flow and heat exchange between the test pieces. This is inconsistent with the reproduction of environmental conditions, because the air flow around the test chamber specimen specified in the relevant standards for temperature and air flow rate environmental tests shall not exceed1.7m/s, to prevent the sample and the surrounding air to produce heat conduction is not realistic, the average wind speed of the no-load test chamber.0.6 ~ 0.8Meters/seconds, no more1m/s) To meet the specified requirements in the ratio of two spaces and areas, the flow speed can be increased (50 ~ 100）%, the average wind speed (1Meters/Seconds1.7 ~1) Meet the standard requirements. If there is no restriction on the increase of the test sample or the cross-sectional area in the experiment, the test speed will be increased until the wind speed exceeds the standard, and the validity of the test results will be questioned.

2、The precision index of the parameters (such as ambient temperature, humidity, salt spray sedimentation rate) in the working cavity of the cold and hot shock test chamber is tested in the no-load state. Once the test sample is put into the test sample, the uniformity of the parameters in the test chamber cavity will affect the test piece, and the greater the space occupation, the more serious the impact. Experimental data show that the flow temperature on the windward and leeward sides can reach3~8 ℃, can be reached in severe cases10Above℃. Therefore, we must try to meet two requirements to ensure the uniformity of the environmental parameters around the test sample.

3、According to the principle of heat conduction, the air temperature near the box wall is usually different from the center temperature of the flow field.2~3 ℃, under the high temperature limit, it can reach5℃. Near2~3 ℃Temperature difference box wall temperature and flow field (box wall structure and material determination) test temperature and the external atmospheric environment difference is greater, the temperature difference is also greater, therefore, the box wall100 ~ 150mmThe space of the scope is an unavailable space.

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