Contact thermal resistance measuring device capable of adjusting loading force and temperature within wide range

Abstract

The invention discloses a contact thermal resistance measuring device capable of adjusting the loading force and the temperature within a wide range. The contact thermal resistance measuring device comprises a measuring unit, wherein the measuring unit is connected to a rack; the bottom of the rack is connected with a universal wheel; a level instrument is placed on the upper surface of the rack; a liquid inlet pipe of the measuring unit is connected to a feed liquid inlet of a liquid nitrogen storage tank through a liquid nitrogen injection pipe; and an exhaust pipe of the measuring unit is communicated to an atmospheric environment through a nitrogen escape pipe. The axial heat flow measurement precision is improved in a high vacuum heat insulation way; the loading force of a contact surface is adjusted within the wide range by using a loading bolt, a thrust bearing and the like; the temperature of the contact surface is adjusted within the wide range by using a liquid nitrogen tank, an electric heating ring and the like; the loading force and the temperature can be adjusted at any time in a measuring process without damaging the vacuum degree; and the contact thermal resistance measuring device has the advantages of accuracy in measurement, wide working condition range, convenience for operation and the like.

Description

technical field [0001] The invention relates to the technical field of measuring thermophysical properties of solid materials, in particular to a contact thermal resistance measuring device capable of adjusting loading force and temperature in a wide range. Background technique [0002] Thermal contact resistance refers to the additional resistance encountered when heat is transferred through the contact interface between solids. The formation mechanism of thermal contact resistance mainly includes the incomplete contact caused by the unevenness of the actual solid surface, and the scattering of heat carriers at the contact interface; the former plays a dominant role in the normal temperature region and the high temperature region, and the latter plays a dominant role in the low temperature region. In aerospace, superconductivity, nuclear power, microelectronics and other technical fields, contact heat transfer between solid interfaces is a commonly used form of heat dissipa...

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Problems solved by technology

For example, Xu Lie et al. (Dual heat flow method to measure the contact thermal resistance of the solid interface under low temperature vacuum. "Cryogenic Engineering". 1999, (No. 4), 185-189.) proposed a method to measure the contact thermal resistance with a double heat flow meter and The device described in this article can easily adjust the loading force outside the vacuum chamber, but the elastic stress of the bellows itself makes it difficult to accurately measure the loading force, especially when the loading force is small; and the device is not easy to realize from the liquid nitrogen temperature zone Continuous temperature control to normal temperature zone

Xu Shengya and Hong Guotong (Experimental research on contact thermal resistance between Cu-Cu interfaces compressed by screws under vacuum and low temperature. "Vacuum and Low Temperature". 2010, Volume 16 (No. 3), 153-156.) proposed that the contact surface The experimental method and device for measuring the contact thermal resistance between the screw-pressed interfaces when the temperature is fixed. The device can simulate the contact conditions of low temperature and vacuum, but the loading force cannot be adjusted outside the vacuum chamber, so it is not convenient to conduct the same test on the same group of test pieces. Temperature, contact thermal resistance measurement of different loading force, also can not get loading - hysteresis change law of contact thermal resistance during unloading process

The device proposed by Huang Haiming et al. (Apparatus and method for simultaneously determining thermal conductivity and thermal contact resistance.2011, CN101887041B.) was loaded with a special press, and Kwabena A.Narh et al. (Apparatus and method for simultaneously determining thermal conductivity and thermal contact resistance.2011 , US6142662A.) The loading force of the device proposed can reach 3MPa; but in the above two devices, the method of wrapping heat insulating material is used to reduce the radial heat dissipation of the specimen. This heat insulation method is worse than the high vacuum heat insulation effect. Surface temperatures much lower than ambient can introduce significant error in the measurement of axial heat flow

The device proposed by Hong Jun et al. (A vacuum contact thermal conductivity measurement device for a fixed joint surface. 2011, CN102141529A.) uses piezoelectric ceramics to adjust the loading force, which is suitable for working conditions where the loading force is not large; the device uses liquid nitrogen to directly cool and refrigerate liquid, and the temperature of liquid nitrogen under normal pressure is about -163°C, which is easy to cause the refrigerant to freeze

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