Výpočet koeficientu přestupu tepla v kontaktu při nestacionárním měření teploty

Estimation of the Thermal Contact Conductance From Unsteady Temperature Measurements

článek v časopise ve Web of Science, Jimp

en

Thermal contact conductance is an important parameter for describing the heat transfer between two bodies. When two solids are put in contact and heat transfer occurs, a temperature drop is observed at the interface between the solids. This is caused by an imperfect joint, which occurs because the real surfaces are not perfectly smooth and flat. This paper describes an experimental device for the evaluation of the thermal contact conductance, which was designed and fabricated in the Heat Transfer and Fluid Flow Laboratory. This device was built mainly for simulating metal-forming conditions, which include high pressures (up to 360 MPa) and high temperatures (up to 1200 degC) in the contact of two solids. The principle of this investigation is the unsteady measurement of the temperatures of two solids that are put in contact under different conditions. The surface temperature and thermal contact conductance can be calculated from the measured temperatures by an inverse heat-transfer task. The measured temperature history and the calculated values of the thermal contact conductance for pilot tests are presented in this paper.

Koeficient přestupu tepla v kontaktu je důležitý parametr pro popis přestupu tepla mezi dvěma tělesy. Pokud mezi dvěma tělesy s různými teplotami dojde ke kontaktu, dojde i k výměně tepla a v místě dotyku je pozorován teplotní pokles. Ten je způsoben nedokonalostí povrchů obou těles. Tento článek popisuje experimentální zařízení, které slouží k měření koeficientu přestupu tepla v kontaktu a metodiku, jak této charakteristiky dosáhnout. Zřízení je konstruována pro dosažení podmínek simulujících tváření kovů (tlak do 360 MPa a teplota do 1200 stupC).Princip měření spočívá v nestacionárním měření teploty těles blízko jejich kontaktu. Ze záznamu teplot je poté vypočítán pomocí inverzní úlohy vedení tepla koeficient přestupu tepla v kontaktu.

Thermal contact conductance is an important parameter for describing the heat transfer between two bodies. When two solids are put in contact and heat transfer occurs, a temperature drop is observed at the interface between the solids. This is caused by an imperfect joint, which occurs because the real surfaces are not perfectly smooth and flat. This paper describes an experimental device for the evaluation of the thermal contact conductance, which was designed and fabricated in the Heat Transfer and Fluid Flow Laboratory. This device was built mainly for simulating metal-forming conditions, which include high pressures (up to 360 MPa) and high temperatures (up to 1200 degC) in the contact of two solids. The principle of this investigation is the unsteady measurement of the temperatures of two solids that are put in contact under different conditions. The surface temperature and thermal contact conductance can be calculated from the measured temperatures by an inverse heat-transfer task. The measured temperature history and the calculated values of the thermal contact conductance for pilot tests are presented in this paper.

koeficient přestupu tepla v kontaktu, inverzní úloha vedení tepla, koeficient přestu tepla

thermal contact conductance, inverse heat conduction problem, heat-transfer coefficient

2015

01.04.2015

Institute of Metals and Technology

Ljubljana, Slovinsko

1580-2949

49

2

219–222

4