Development And Investigation On Heat Transfer Performance Of Thermosiphon Pipe Array With Non-concentrical Tube

Gravity heat pipe, also called thermosiphon, is a highly efficiency heat transfercomponent in which heat is transported by phase-change of the working fluid. Heat pipeor thermosyphon has been widely applied in chemical plan, power industry, electronics,energy-saving, and natural energy utilization for its excellent heat transfer performance,simple structure, high adaptability to the environment, low cost and good reliability.With the demanding of development of energy efficient utilization and heat transferenhancement technology, various kinds of the heat pipe with different application isbecome a research focus. Literature shows that increase evaporation and condensationheat transfer area could improve the heat transfer performance of gravity heat pipe.Based on this concept, a novel gravity heat pipe application structure is proposed inthis paper. The structure difference between this thermosyphon array and traditionalgravity heat pipe is that many evaporation tubes shares one horizontal condenser pipewhich perpendicular to them, as well as a cooling water tube out of it. This structureexpands the condensation area and the working fluid is regulated in the comparativelyseparate evaporation tubes.Systematic experimental research and analysis of the heat transfer performance ofthis thermosyphon array has been conducted in this work. The work done includesdetermination of the thermal performance of the developed device and various influentfactors like the slant angle, evaporation length, evaporator heat flux, operatingtemperature on the maximum heat transport capacity, boiling and condensing heattransfer coefficient and thermal resistance. The results showed that the optimal angle ofinclination of this thermosyphon pipe array is between60°to75°; when the evaporationlength=270mm, the heat transfer performance of this thermosyphon pipe array wasbetter than other evaporation lengths; with the rise of operating temperature，itsmaximum heat transport capacity and heat transfer coefficient also increased，thermalresistance reduced, and the temperature uniformity of evaporator wall also improvedgreatly; evaporation section heat flux also had a big effect on its heat transferperformance, under a big heat flux, evaporator heat transfer process appeared oscillation.In the best conditions, the boiling heat transfer coefficient of this thermosyphon pipearray was much bigger than traditional single gravity heat pipe.This investigation not only has done a fundamental research material for furtherimprovement about this device, but also provided a serious useful data which will be helpful to the application of this new type composite structure of gravity heat pipe inindustrial heat recovery and the design of large-scale heat pipe exchanger.