Study On Fluid Flow And Heat Transfer Performance Of Pulsating Heat Pipe Under Vibration

As a new type of heat transfer component,the pulsating heat pipe(PHP)has numerous advantages and is widely used in various radiating fields.In practical engineering applications,most of the radiating devices are inevitably affected by the vibration from external environment.Thus,to conduct an experimental study on flow and heat transfer performance of pulsating heat pipe under vibration and to obtain a method of reducing the influence of vibration on the heat transfer performance of the pulsating heat pipe is particularly necessary.Currently,the difference between the vapor-liquid two phase flow in the pulsating heat pipe of different pipe inner diameters has not been verified.The influence of different vibration parameters on the heat transfer performance of the pulsating heat pipe is still lack of quantitative rule.The method to enhance the heat transfer performance of pulsating heat pipe under vibration is not clear.Therefore,three experimental studies were designed and conducted in this article.Firstly,the influence of different inner diameters on the flow and heat transfer characteristics of the pulsating heat pipe was explored.Secondly,the internal mechanism of the influence of different vibration parameters on the flow and heat transfer characteristics of the pulsating heat pipe was revealed.Finally,the heat transfer characteristics of the structurally optimized pulsating heat pipe under vibration are tested and the design idea of the anti-vibration pulsating heat pipe in practical engineering application is given.The main contents of the research and conclusions of this paper are shown as follows:(1)The visualization experimental study on the flow and characteristics of the pulsating heat pipe with different inner diameters show that the increase of the inner diameter will decrease the capillary instability of the vapor-liquid interface,which will make the bubble segment break easier.Under the same heat input,the 1mm diameter pulsating heat pipes usually has higher thermal resistance,and the ultimate heat input that they can sustain is lower than that of the 2mm and 3mm diameter pulsating heat pipes.(2)The experimental study on the flow and heat transfer performance of pulsating heat pipes under vibration shows that the effect of vibration on the pulsating heat pipe increases with the increase of the pipe diameter.Vibration under low heat load has a strengthening effect on the pool boiling phenomenon in the pulsating heat pipe,so its heat transfer performance is enhanced;under the high heat load,the inertial force of the vibration environment is not enough to resist the driving force of the pressure difference inside the pipe,so the vibration to the pulsation under high heat load The effect of heat pipes is small.(3)The experimental study on the vibration-adaptive enhancing method of pulsating heat pipe shows that the pulsating heat pipe coupled with the capillary core structure inside the inner wall not only has excellent adaptability to the vibration environment,but also has the uniform temperature performance and heat transfer performance far beyond the traditional structure pulsating heat pipe.Thus,a new solution for the design of pulsating heat pipes under vibration for practical applications in subsequent projects was provided.