Heat Transfer Characteristic Of A Pulsating Heat Pipe At Liquid Hydrogen Temperature Range

Superconducting technology has been widely developed since the100years after the discovery of superconductivity. Cryogenics is the key technology for the application of superconductivity, which is used for cooling the superconducting magnets. Recently, directly utilizing cryocooler is the most common method. While an efficiently cooling transfer method connected with cryocooler is needed because of the large area and long distance of the cooling object. Pulsating Heat Pipe as a high efficient heat transfer method was widely concerned in the past twenty years, especially at room temperature. Recently many scholars have actively thought of the possibility of the application of cryogenic pulsating heat pipe.MgB2which was discovered at2001is expected to replace some high temperature superconductor at25K. The research of liquid hydrogen range is significant for the application of MgB2.Therefore, this paper proposes a hydrogen pulsating heat pipe and carries out the following work.Firstly, this paper summarizes the previous researches about the cryogenic pulsating heat pipe, and presents the research contents and directions. Based on the theory of the pulsating heat pipe at room temperature, this paper explores the mechanism of the hydrogen pulsating heat pipe, which directs the experiment setup design.Then, we design and build a hydrogen pulsating heat pipe utilizing the software of ANSYS, EES and Solidworks. This experimental setup is composed of filling and vacumm device, cooling device, and data acquisition device and heat pipe system. Heat pipe system is the main part of the setup including of dewar, copper shield and pulsating heat pipe element. Then the pulsating heat pipe element is main part which is composed of condenser, evaporator and capillary pipe. Moreover, this paper simulates the temperature distribution of the copper shield and checks the mechanical strength of the rod, all of which meet the requirements.Finally, through the experimental study we explore the influence of the filling ratio and heat input on the performance of the cryogenic pulsating heat pipe at liquid hydrogen range. The conclusions we get from the experiment are listed as following.1. The efficient thermal conductivity increases depends on the increasing of the heat input when the pulsating heat pipe starts pulsating.2. The maximum thermal conductivity equals19371.440W/m-K and the temperature difference is0.280K when the heat input is1.280W at the filling ratio of34.22%.3. The maximum thermal conductivity equals17952.360W/m-K and the temperature difference is0.520K when the heat input is2.205W at the filling ratio of56.34%.4. There is a better heat transfer performance of a hydrogen pulsating heat pipe at filling ratio of34.22%than56.34%.All of these verify the feasibility of a pulsating heat pipe at liquid hydrogen temperature range.