Papers by Keyword: Heat Pipe

Abstract: This paper proposed an energy-saving system which combination solar collectors for heating water system with heat pipe heat exchanger to recover kitchen waste heat. Its working principle is using heat pipe exchangers exhaust heat to warm the cold water from water storage tank, and during the day, take advantage of solar collectors to help heat pipe heat exchanger heating the water. In this design, the heat exchanger tank and the heat storage tank arranged independently, water tank associated control system was provided with automatic temperature regulator to control the opening and stopping of the pump. This system made full use of kitchen waste heat and solar to meet the kitchen cooking and cleaning process hot water supply needs.

Abstract: With an urgent need for energy conservation and pollution reduction, the trend of replacing traditional incandescent or fluorescent lamps with high-power LEDs is growing more and more popular. However, heat dissipation of high-power LED is the main bottleneck for its application. In this research, a kind of automotive headlamp low beam system model is designed with high power LED chips. Several different cooling devices are designed for headlamp cooling, the heat dissipation performances are simulated and analyzed both by the finite volume method (FVM) in FloEFD and experimental measurements. The obtained results indicate that loop heat pipe combined with fined heat sink is the most effective way for heat dissipation in the designed automotive low beam system, even in 80¡æ environmental temperature can ensure the LED headlamp system working stability. The research lays a theoretical basis for the follow-up study.

Abstract: The aim of this study is to optimize the cooling device for high power LED headlamp. The feasibility of using SMD (Surface Mounted Devices) resistor instead of LED chips has been analyzed by FloEFD and the relationship between temperature and total input power has been found. In order to evaluate the cooling performance of the heat pipe, two different arrangement forms has been used. Based on the simulation, heat pipe arranged in rectangle can satisfy the requirement of high-power LED headlamp. These results also laid a theoretical foundation for later experiments.

Abstract: The grinding hardening is a new technology which utilized thermal of grinding zone to heat-treat the workpiece surface layer. In grinding hardening process, grinding zone temperature directly affects the quality of surface layer of heat treatment. The high temperature heat pipe is very good device of control heat transfer. In order to make the grinding zone temperature slightly change in grinding process, this paper describes a design of temperature automatic control technology. A high temperature heat pipe contact with the workpiece’s grinding zone. The zone temperature is measured using infrared radiation pyrometer and the temperature data will be used to control the high temperature heat pipe’s thermal resistance through the PID controller. That is that the PID controller will adjust the contact area between workpiece and high temperature heat pipe, thus achieves control of workpiece’s surface hardening requirements.

Abstract: This paper describes the structure of heat pipe cooled hot forging die. A computational method was used to predict the temperature field of the die structure model. The research results show that the heat pipe can be effective cooled hot forging die, the temperature values of around heat pipe have a declining greater, thus significantly reducing the thermal load of the hot forging die, to further extend the life of the die.

Abstract: According to the principle of heat transfer to set up corresponding model of lumped parameters, and calculate the heat production of proton exchange membrane fuel cell. Under the steady state condition, with the help of numerical simulation and calculation in Sinda/Fluent,heat which from the internal of battery can be diffused through the heat pipe,especially dealing with issues such as local overheating. The result of this research shows that the use of the technique of liquid phase change heat transfer in the close room can have a high heat transfer efficiency, also start quickly and isothermal performance is good, the finally , its control is simple and it is very suitable for heat removal of PEMFC battery pack.

Abstract: In this paper, the effect on the thermal efficiency enhancement of a heat pipe using SiO₂-water nanofluid on different operating states was investigated. SiO₂-water nanofluids with mass concentrations of 0.1% ~ 2.0% have been prepared with the average size of 10nm, 30nm, 50nm, 70nm, respectively. Heat transfer characteristics of the heat pipe including wall temperature distribution, heat transfer coefficient and thermal resistance have been investigated, which showed excellent properties.

Abstract: This paper reports on thermal characterization of edge illumination type LED backlight integrated with heat pipes. Heat pipe is integrated with the panel by phase change flattening and expanding process. Thermal capabilities, including the steady-state working temperature and the temperature uniformity along the panels with heat pipes and without heat pipes are compared and analyzed. Results show that the steady-state working temperature on the panel with heat pipes is 1~6°C lower than that on the panel without heat pipes under power range of 15W to 51W of the LED arrays. And the temperature uniformity along the panel with heat pipes is controlled within 2.0°C.

Abstract: In the precision hot plate for wafer processing, the temperature uniformity of upper plate surface is one of the key factors affecting the quality of wafers. Precision hot plates require temperature variations less than ±1.5% during heating to 120°C. In this study, we have manufactured the flat plate heat pipe hot chuck of circle type (300mm) and investigated the operating characteristics of flat plate heat pipe hot chuck experimentally. Various screen mesh (40, 80, 120) were used as the structure and chamber was changed.

Abstract: In the present study, TiO₂-nanofluid with different volume ratio was used as working fluids of thermosyphon and grooved heat pipe to investigate working stability. The stability behavior of system was studied with various parameters such as volume concentration of nanoparticle, orientation, heat flux, and cooling media were investigated. Specially, the present experimental unstable working behaviors between TiO₂-nanofluid and pure water were compared. In the present study, the TiO₂-nanoparticles were dispersed into pure water with each of cross blended concentrations of 0.05%, 0.1%, 0.5%, and 1%. In the present study, the rate of growth of unstable disturbances is expressed in terms of temperature perturbation. The best stable operation was observed with thermosyphon of 0.5 % TiO₂-nanofluid. The best operation state with nanofluidic TS was observed in the 90° inclination and α = 0.5. In the present study, the enhancement of heat pipe performance with TiO₂-nanofluid is presented. The both heat pipes were fabricated from the straight stainless pipe with the inner diameter and length of 10, 500 mm, respectively.