Inverse thermal analysis of the drying zone of the evaporator of an axially grooved heat pipe

• Published in: Experimental thermal and fluid science 2010-07, Vol.34 (5), p.562-574
• Main Authors: Lataoui, Zied, Romestant, Cyril, Bertin, Yves, Jemni, Abdelmajid, Petit, Daniel
• Format: Article
• Language: English
• Subjects: Adiabatic flow; Applied sciences; Devices using thermal energy; Dry out front; Drying; Energy; Energy. Thermal use of fuels; Evaporation; Evaporative; Exact sciences and technology; Grooved; Heat pipe; Heat pipes; Inverse; Inverse method; Temperature gradient; Temperature measurements
• ISSN: 0894-1777; 1879-2286
• DOI: 10.1016/j.expthermflusci.2009.11.009

An inverse approach is performed to characterize the thermal behaviour of an axially grooved heat pipe, in steady state, for various operating conditions. For this purpose, an experimental set up, as well as a network conduction model, are developed to simulate the heat transfer in the wall at the evaporator section. The minimization of an objective function, taking into account the discrepancy between measured temperatures and computed ones, allows then the estimation of a heat transfer coefficient as well as the drying out front positions for all the axial grooves. Hence, at the burnout point, the significant temperature increase in the evaporator extremity is considered to be a direct consequence of the restriction of the evaporative zone. Therefore, the distribution of liquid phase in the capillary structure of the heat pipe can be obtained through the analysis of the measured temperature gradient in the evaporator section where the dry out front was expected to occur. Furthermore, the dry out front expansion can be observed when the input heat load is increased or when the adiabatic temperature is decreased. Introducing an adverse tilt angle also shows the effect of the puddle.