Experimental Study on Heat Transfer Enhancement of Variable Speed Motion Phase Change Capsules
In order to study the effect of variable speed motion on heat transfer enhancement of phase change capsules,the cylindrical phase change capsules were prepared by using hexadecane as phase change material and brass as shell.The crank rocker reciprocating device was used to realize the variable speed movement and build the experimental platform;phase change capsules were designed experimental-ly in the process of charging and discharging of the temperature range of 10-30 ℃,with the direction of variable speed movement along the capsule axial or radial reciprocating motion,amplitude of 6-12.5 mm,and frequency of 1.55-3.78 Hz.The influence of variable motion direction,amplitude and fre-quency on capsule charging and discharging effects was analyzed by measuring the temperature data uni-formly distributed at eight measuring points on the inner axis of capsule.The experimental results show that the heat transfer of phase change capsules is significantly enhanced by variable speed motion.Com-pared with the static state,the heat transfer coefficient can be increased by up to 35.6％in the experi-mental range;the effect of enhanced heat transfer is better when the capsule moves along the radial direc-tion than that along the axial direction,and the heat transfer time can be shortened by 26.7％at most;the discharging time of capsules under different working conditions is higher than the charging time.In-creasing amplitude and frequency can effectively improve the efficiency of charging and discharging,and has a more significant impact on the charging process.
heat storagephase change materialcapsulevariable motionenhancement of heat transfer
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