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The temperature distributions of solid parts in motorcycle is of significance to give an quantitative cooling performance evaluation for assuring the feasible running of motorcycles. Therefore, the present work mainly tend to systematically investigate the flow velocity distributions and temperature distributions of motorcycle by constructing a fluid-solid coupling analysis model via CFD using commercial software STAR-CCM+. Based on computational fluid dynamics method (CFD), fluid-solid coupling analysis model of motorcycle is realized by integration of porous media model, heat exchanger model and fluid-solid co-simulation module and numerical investigations on fluid flow and temperature distribution characteristics at maximum running speed 120 km/h is conducted. The thermal management experiment test considering three pressure measuring points, fifty-eight temperature measuring points and two flowrate measuring points is investigated to know its cooling performance of motorcycle experimentally and provide experimental data for validation of simulation model. Results show that CFD results are in good agreement with experimental results and the maximum relative error is less than 10%. Thermal management test results show that left and right cylinder temperature, oil temperature are 183 °C, 190 °C, 120 °C, respectively. Air temperature of radiator at inlet side are from 29 °C to 35 °C, Air temperature of radiator at outlet side are from 60 °C to 90 °C, water temperature of radiator inlet and radiator outlet are 96 °C and 89 °C, respectively. The air temperature around left thigh and right thigh are 31 °C and 34 °C, respectively. CFD results show that there is no flow dead-zone and high temperature area in engine main components and muffler front cover. The temperature around motorcycle covering and both two thigh is not high due to the radiation of high-temperature components and the outlet temperature of exhaust muffler is also not high, which will not cause enough heat feelings to the riders for being uncomfortable. From the temperature field analysis results, there is no obvious poor temperature distributions for thermal comfort of this motorcycle. The results of this work can provide simulation data support and theoretical reference for the design and development of motorcycle and its crucial components. Through engineering applications of fluid-solid coupling model in a two-cylinder engine and electric generator, it verifies the universality of fluid-solid coupling model and it can be an effective way for the temperature predictions of industrial products. [ABSTRACT FROM AUTHOR]

Achieving an optimal cooling of the generator unit is indispensable for high working performance. In this work, computational fluid dynamics analysis on the flow field of the conventional type and silent type of the S688CCS series generator unit is conducted, and design optimization of the generator unit with poor cooling is studied based on flow field analysis results. Flow field simulation results indicate that the total cooling air quantity of the silent type generator unit is lower than that of the conventional type generator unit, and the cooling air quantity of the radiator is also lower than that of the conventional type generator unit, which is not conductive for the cooling of the silent type generator unit. The flow field optimization is achieved by adopting the single variable control method to improve the structure of the fan cover, silent components for silence, adjacent structure, and air inlet grille. The corresponding structure optimization scheme is put forward. After optimization, the air quantity for the cooling radiator of the silent type generator unit is 44.33% higher than that of its original structure, and the total cooling air quantity is higher than that of the conventional type generator unit. The research results in this work can provide a theoretical basis for the design of the cooling air flow path of generator units for achieving an optimal cooling performance. [ABSTRACT FROM AUTHOR]

A three-dimensional model of the steam ejector heat pump for the dryer section of the paper machine was developed by applying the Computational Fluid Dynamics (CFD) technique, which provided the pressure and velocity distributions of fluid flow in heat pump. The results indicated that the fluid velocity field in heat pump has an incomplete axially symmetrical distribution. The entrainment ratio of the heat pump initially increases rapidly with the increase of the ejected steam inlet pressure and then decreases after the inlet pressure exceeds one certain value. There exists a critical value for the mixed fluid pressure under the given operating conditions. The optimal ratio of the diameter of constant area mixing section to the steam nozzle throat diameter is about 3.4 and the optimal ratio of length to diameter of constant area mixing section L/D m is 6. An optimal divergence angle of diffuser was observed under different diffuser length. There is an optimized steam nozzle position under the given operating condition where the maximum of entrainment ratio was observed. The CFD technique is found to be an efficient alternative to predict the ejector performance and the conclusions of the research can provide a beneficial reference for structural optimization design of ejector. [ABSTRACT FROM AUTHOR]