Experimental Study Of The Start-up Characteristics And Heat Transfer Performance Of The Dual Compensation Chamber Loop Heat Pipe

The Dual Compensation Chamber Loop Heat Pipe(DCCLHP)is different from traditional loop heat pipes in that it is equipped with two compensation chambers,which can supply the evaporator from any direction.Therefore,it has great potential for application in the future of space thermal management.However,the DCCLHP suffers from a high thermal resistance,which makes it a challenge to start up under small thermal loads.Furthermore,severe backward heat leakage from the capillary wick hinders the DCCLHP’s start-up and operation.To ensure reliable start-up and efficient heat transfer in the microgravity environment of space,this paper experimentally validates a DCCLHP with an eccentric structure of a silicon nitride capillary wick.This study focuses on the experimental investigation of the DCCLHP’s start-up characteristics and steady-state heat transfer characteristics,as well as providing an in-depth analysis of the factors that affect the DCCLHP’s start-up and steady-state heat transfer characteristics.In this experimental study,we investigated the heat transfer characteristics of DCCLHP by designing a system.We systematically examined how the placement orientation,starting power,and heat sink temperature affect the starting behavior of DCCLHP using theoretical analysis and experiments.Our findings demonstrate that the appearance of two initial gasliquid distributions inside the evaporator in all six placement attitudes.As such,the DCCLHP has two start-up conditions.Moreover,the DCCLHP can achieve a fast start-up with a small thermal load of 2W,regardless of its placement attitude,while having good thermal response characteristics.In addition,an increase in start-up power decreases the DCCLHP’s start-up time,while increasing the temperature overshoot and then decreasing it,exhibiting an inverted "V" pattern.A higher heat sink temperature results in a shorter DCCLHP start-up time and a smaller start-up overshoot,hence aiding in the DCCLHP’s start-up.Furthermore,the overall temperature of the DCCLHP system increases with a rise in the heat sink temperature.In this study,we conducted variable power experiments on the DCCLHP to verify its heat transfer limit and reliability,estimate parameters related to heat transfer characteristics,analyze the impact of various factors on parameters like operating temperature and thermal resistance,and examine the effect of the reservoir on DCCLHP operating behavior from an energy balance standpoint.Our findings indicate that the DCCLHP’s heat transfer limit exceeds 400 W for all six placement attitudes,with the maximum limit exceeding 450 W.The thermal resistance’s distribution of the DCCLHP is constant for all attitudes,with minimum values of 0.051°C/W and an "L"-shaped distribution.When using variable power,the evaporator rapidly adapts to a new value while remaining stable,and the temperature difference between evaporators at the same power output does not exceed 1°C,indicating that the DCCLHP effectively regulates temperature and has strong variable heating power reliability.Energy balance analysis demonstrates that the equilibrium temperature curve of the two reservoirs of the DCCLHP coincides with the standard operating characteristic curve of a loop heat pipe.Furthermore,smaller temperature differences lead to greater heat transfer performance in the DCCLHP.A silicon nitride wick dual compensation chamber loop heat pipe(DCCLHP)with an eccentric structure is proposed in this study.This provides a valuable reference for the application of DCCLHP in microgravity thermal management in space.