Heat generation and transfer simulation of a high temperature heat pipe under induction heating based on a coupled model

Abstract

High temperature heat pipes are highly efficient heat transfer devices, and induction heating is often utilized in their performance tests. However, issues exist in evaluating the equivalence between induction heating and surface heating encountered in typical application scenarios, and in quantifying the accurate input heat flux of induction heating. In order to identify the key influencing factors and investigate their effects on heat generation and transfer within high temperature heat pipes under induction heating, a finite element thermal-electrical coupled model is developed based on the pseudo wick thermal conductivity model and electromagnetic theory. The effects of frequency (10 kHz, 100 kHz, 300 kHz), loaded current (10 ∼ 890A), cooling coefficient (10 ∼ 250Wm-2K−1) and temperature (300 ∼ 1000 K) are investigated. Over 98% of the induction heat is found to be generated in the evaporator section, with a considerable proportion generated in the annular channel (38 ∼ 52%) and the capillary wick (23 ∼ 26%) at low frequency (10 kHz). The wall temperature of the evaporator section is slightly lower than the temperature of the annular flow channel or even the capillary wick at weak cooling boundary conditions (<130Wm-2K−1@10 kHz, <50Wm-2K−1@100 kHz, <30Wm-2K−1@300 kHz). Quantitative calibration formulas of induction heat are established in relation to frequency, current, and temperature via two sets of quadratic polynomial fitting. The results can be used as reference for design and evaluation of transient and steady-state tests of heat pipes under induction heating.