Tham khảo tài liệu 'heat analysis and thermodynamic effects part 11', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Micro Capillary Pumped Loop for Electronic Cooling 289 The test condition in Fig. 22 was the weak heat dissipation at the condenser. That is the cooling water was not circulated at the condenser in order to investigate only the normal operating characteristic of the micro CPL by phase change of the working fluid. In the case of the heat pipe with the mechanism of vapor-liquid phase change the heat pipe shows isothermal characteristics which transfer a lot of heat in small temperature difference between the evaporator and the condenser. Therefore the normal operating state could be confirmed by measuring the temperature difference between the evaporator and the condenser when small power is input to the evaporator. In Fig. 22 the micro CPL with working fluid shows lower thermal resistance than the micro CPL without working fluid in both cases of total length being 50 mm and 70 mm. This means that the fabricated micro CPL in the present study operates normally through the operating mechanism of vaporliquid phase change. In the case of the total length of 50 mm the micro CPL with working fluid shows lower thermal resistance about half of that of the micro CPL without working fluid. In the case of the total length of 70 mm the micro CPL with working fluid shows lower thermal resistance about a third of that of the micro CPL without working fluid. This means that although the total length is increased from 50 mm to 70 mm the micro CPL with working fluid operates normally by vapor-liquid phase change. However the thermal resistance of the micro CPL increased when the total length was changed from 50 mm to 70 mm. Fig. 22. Comparison of thermal resistance between the flat plate type micro CPL with working fluid and the one without working fluid Fig. 23 shows the comparison results for the heat transfer rate between micro CPLs with working fluid with total length of 50 mm and 70 mm. In Fig. 23 the input power was not the maximum heat transfer rate the heat transfer rate .
