Papers by Keyword: Enhanced Cooling

Abstract: In order to solve cylinder-scraping of a four-cylinder high speed diesel engine, based on the measurement of piston temperature, the piston temperature field was numerically simulated by using temperature fitting method, the calculation results were well consistent with the measured temperature. By finite element analysis of piston thermal load based on the calculation results as temperature load, enlarging oil cooling cavity in the piston head was proposed to enhance cooling locally, which could effectively reduce temperature of the piston head and the first ring groove and avoid the occurrence of cylinder-scraping.

Abstract: High power LED headlamp cannot operate normally and efficiently in case the maximum junction temperature exceeds 120°C. Therefore, it is essential to install external cooling device with excellent thermal management. A model based on plate-fin heat sink is presented, the heat transfer plates (HTPS) are added to bridge aluminum substrate and heat sink. And its thermal performance is evaluated compared with the one only installing heat sink. Results reveal the HTPS coupled with heat sink has a good cooling performance. In addition, the correlation between the junction temperature and the HTPS length is investigated. The optimum length is 47 mm. Furthermore, considerable simulation and experiment are conducted on the junction temperature variation subject to input power, ambient temperature, as well as the installation angle respectively. Finally, a fan is added based on the original device to enhance cooling. It indicates that the junction temperature decreases gradually with the presence of velocity air flow.

Abstract: An experimental study was performed to analyze the feasibility of heat pipe cooling in creep feed grinding applications. A new type of grinding wheel is developed to enhance the heat transfer of the grinding contact zone then decrease the grinding temperature. The performance of the new type grinding wheel was evaluated by measuring the grinding temperature when it was creep feed grinding the Ti-6Al-4V Alloy and the experimental results were compared with an ordinary grinding wheel. Results of the comparative study indicated that the use of enhanced cooling technology in a grinding wheel can decrease the grinding temperature significantly thus avoid the surface burning in grinding.

Abstract: This paper develops a 2D finite element model for the enhanced cooling cutting of stainless steel. The enhanced cooling effect is modeled with a convective heat transfer coefficient assigned to a heat transfer window of cutting zone. Five convective heat transfer coefficients are defined to simulate different enhanced cooling effects. The simulation results suggest that increase of convective heat transfer coefficient results in a very small reduction of maximum tool-chip interface temperature, even when a very large convective heat transfer coefficient is used. In addition, no significant effect on cutting force and thrust force is observed with the increase of convective heat transfer coefficient.

Abstract: Experiments of the valve bridge are carried out and the boiling states are investigated, to study the boiling heat transfer in cylinder head jacket. The effects of inlet flow rate and temperature on boiling heat flux are analyzed, as well as the thickness of fire deck. The results show that the inlet velocity has little effect on the velocity in valve bridge zone, even the velocity in the valve bridge zone can strongly affect on boiling heat transfer. The results can offer references to practical application in power-enhanced diesel engine.

Abstract: To evaluate the efficiency of drilled cooling in the valve bridge of cylinder head, theoretical analysis for the drilled cooling is carried out, and a mathematical model for the enhanced cooling is presented based on a simplified 3D model. The mathematical model is validated by numerical study on the heat transfer with and without drilled cooling, which is carried out through fluid-solid coupling. The correlation between the velocity in the drilled passage and heat transfer coefficient was also analyzed. The results can be used to solve the heat transfer in enhanced diesel engine.