Thermal Management On High-power Electronics Of The Logging Tool In High Temperature Environment

Logging tools are used to explore the distribution and reserves of oil and gas resources underground,which need to operate in extremely high-temperature downhole environment(?200?)for 6-9 hours.The working temperature of the high-power electronics of the logging tool cannot exceed 125?,so they often face the problem of thermal failure in such high-temperature environment.Researchers at home and abroad usually use thermal management to protect the internal electronics of logging tools,but generally focus on lowpower electronics,and there is a lack of research on thermal management of high-power electronics in logging tools.In order to solve this problem,this thesis has carried out research on high-power electronics of logging tools in high-temperature environment,including two parts: heat conduction and storage integrated thermal management system and liquid cooling combined with phase change thermal management system.The specific research content and main results are as follows:1.The heat conduction and storage integrated thermal management system is established,and its thermal performance is studied by numerical simulation combined with experiment.The simulated results show that the heat source temperature of the heat conduction and storage integrated thermal management system reaches 133.4? after working at 205? for 9 hours,which is 32.4? lower than the traditional finned heat dissipation method.In order to further strengthen the heat transfer,the heat source temperature can be reduced to 110.7? by inserting heat pipes into the phase change material,which is further reduced by 22.7?.Then the experimental test is carried out,and the relative error between the experimental results and the simulated results is within 5%.After 9 hours of experimental test,the temperature of the heat source reaches 109?,lower than the failure temperature of electronics.2.The liquid cooling combined with phase change thermal management system for high-power electronics of the logging tool is designed,and its thermal performance is evaluated by numerical simulation,compared with the heat conduction and storage integrated passive thermal management.The results show the flow velocity has a great influence on the temperature control ability of this system.The flow velocity increasing from 0 to 1 m/s,the heat source temperature decreases from 340.6? to 80.04?,but as the flow velocity increases,the temperature control ability is limited;The smaller the pitch of the pipeline in the phase change material is,the better the temperature control ability is;Selecting hydrated salt as phase change material is more beneficial to enhance the temperature control ability of this system;the temperature control ability of the system will deteriorate with the increase of the heat source power consumption.Compared with the heat conduction and storage integrated thermal management system,the heat source temperature of the liquid cooling combined with phase change thermal management reaches 81.7?,with a drop of 29.0?,and the temperature difference between the heat source and the phase change material decreased from 30? to 8.5?,indicating that the liquid cooling combined with phase change thermal management system has stronger heat dissipation capability for the downhole high-power electronics.