Advanced Materials Research Vols. 614-615

Abstract: Fin widely used in industrial practice, and the surface heat transfer coefficient is not constant value. In this paper, through appropriate simplification, the mathematical model in Longitudinal Fin of Rectangular Profile has been established, When the surface heat transfer coefficient along the fin in the exponential changes. The exact solution of fin conduction has been get, and derived efficiency and the corresponding fin heat flux formula. And an example has been given to verify. The solution can be applied to engineering practice, and guided theoretical the heat transfer enhancement in the design of fin.

Abstract: Numerical simulation was used to analyze and calculate the outlet flow field of DRB-4Z type dual channel swirl burner. The results indicate that the recirculation zones become shorter, the diameter of the recirculation zones and the flow divergent angle decrease with the rising of the primary air velocity. Too lower primary air velocity causes the mixing of primary air and secondary air become weaker, which goes against the stable ignition of pulverized coal. With the increase of the outer secondary air blade angle, the flame length increases obviously. The mixing of primary air and outer secondary air is delayed, which decreases the combustion stability. Too small angle of the outer secondary air causes the generation of recirculation zone in the center of flame tail, which has adverse effect on the combustion stability. The attenuation of the highest axial velocity and tangential velocity become faster with decreasing of outer secondary air blade angle.

Abstract: This paper configures rectangular micro channel porous pipe gas cooler model by numerical method, and adopts finite-element analysis and bursting test method to make intensity checking of main components of gas cooler, and make real rectangular micro channel porous pipe gas cooler at the same time by configuration technique of infiltration seal weld and “pierced flanging”. Through heat transfer test of gas cooler, it obtains the surface temperature field of rectangular micro channel porous pipe gas cooler, and makes analysis of the temperature distribution in nearby area of entrance and exit and influence of forced cooling to gas cooler heat transfer.

Abstract: The simulation experiment system of permafrost regions with low temperature environment and the temperature evenness test system of heat pipe were established and researched experimentally. The temperature evenness of heat pipe using magnetic nano-fluids as the working medium and the traditional heat pipe were comparative analysised at the simulation environment of permafrost regions with low temperature. The experiment results show that the heat pipe using magnetic nano-fluids as the working medium has better thermal conductivity, less heat transfer temperature difference, and the more heat transfer ability, more widely applicable temperature range, more applicable to the life and the higher working efficiency. The results provide a new idea to develop higher efficiency heat pipe having the better temperature evenness.

Abstract: The quantity of jaw crusher teeth plate consumed in crashing process directly affects the costs. Based the FEM method, the 3-D jaw crusher teeth plate shape model is established in this paper. This paper studies the stress distribution laws with three types of teeth shape. Through contrasting the results of analysis and data of malfunction teeth plate, it is can be drawing that the stress distribution laws, which can be used in optimizating design of teeth plate shape. It extends the using life and improves the crushing efficiency.

Abstract: In this study, the effect of injection timing on combustion characteristics of a direct injection, electronically controlled, high pressure, common rail, turbocharged and intercooled engine fuelled with different pistacia chinensis bunge seed biodiesel/diesel blends has been experimentally investigated. The results indicated that brake specific fuel consumption reduces with the increasing of fuel injection advance angle and enhances with the increasing of biodiesel content in the blends. The peak of cylinder pressure and maximum combustion temperature increase evidently with the increment of fuel injection advance angle. However, the combustion of biodiesel blends starts earlier than diesel at the same fuel injection advance angle. At both conditions, the combustion duration and the peak of heat release rate are insensitive to the changing of injection timing.

Abstract: To a molten carbonate fuel cell/ gas turbine hybrid system, operating temperature which has significant influence on the performance and lifespan of system is researched. The decoupling control of multivariable system is proposed in the temperature control of a hybrid system. In the designing of decoupling controller, the intelligent decoupling method is used based on Quasi-Diagonal Recurrent Neural Network-PID. Simulation results show that the operating temperature of hybrid system can be effectively close to the desired setpoints based on the decoupling controller.

Abstract: The flow field structure and aerodynamic forces of trains with aerodynamic brake in cross-wind after simplifying the train’s model are studied. Three-dimensional Reynolds average N-S equations (RANS) combining k-ω turbulence model is adopted. The SIMPLE method is used to couple the pressure and velocity. Firstly, the train’s flow field’s variation discipline caused by the aerodynamic brake is analyzed. Then the side force, lift force and rollover moment acting on the train with aerodynamic brake and the one without aerodynamic brake are compared on condition of various wind direction angles. The influence of the aerodynamic brake on trains’ aerodynamic forces and derailment coefficient on condition of various wind direction are analysed. It comes to a conclusion that the derailment coefficient of the train with aerodynamic braking is truly increased but only slightly increased and all the derailment coefficients are under 0.8 which satisfy the safety request of the train’s running safety.

Abstract: In this work, based on the concept of spray-orientation and space-atomization, a new double-layers diffluent combustion system for diesel engine is proposed which has a collision table with circular oriented-surface. Experiments are carried out on a 135 single-cylinder diesel engine by utilization of the new combustion system which is equipped with a high-pressure common-rail fuel injection system. The optimized rail pressure and fuel injection advanced angle are selected for diesel engine at different work conditions. Comparing with the data of original combustion system, the decrease of the brake specific fuel consumption and soot emission is 3.10% and 31.8% respectively while the NOX emission increased by 8.49% at rated work condition for this new combustion system. These results indicate that the new double-layers diffluent combustion system can preferably optimize the performance of diesel engine.

Abstract: The changing tendency of engine performances in its operational range can be directly showed in the engine universal performance characteristics map. Taking advantage of MATLAB mathematic operation, data from engine characteristic tests are processed and the method is simple and credible. The universal performance characteristics map is intuitionist and perspicuous, and is in good fit with data got in tests. It provides a reliable and efficient tool to research into engine performances and automotive drive and fuel economy benefits.