A local composition expression has been derived from the Guggenheim′s quasi-chemicalequation.On this basic a thermodynamic model,the quasi-chemical local composition model(QCLC)was established.To examine its capabili...A local composition expression has been derived from the Guggenheim′s quasi-chemicalequation.On this basic a thermodynamic model,the quasi-chemical local composition model(QCLC)was established.To examine its capability for correlation and prediction,Baxter′s adhesivehard sphere mixtures were used,and an improved numerical method was proposed to estimate theirthermodynamic properties.By means of this method the excess properties of the mixtures composedof four kinds of adhesive hard spheres were calculated,The activity coefficients from QCLC modelwere compared with those from the Wilson,NRTL and UNIQUAC equations.Results show thatamong these models,the QCLC model is the best one for correlation and prediction.展开更多
The mechanical losses in an internal combustion engine cause a significant decrease in the engine’s overall efficiency. Wherever friction work is dissipated a heat load will inevitably appear. This heat load has to b...The mechanical losses in an internal combustion engine cause a significant decrease in the engine’s overall efficiency. Wherever friction work is dissipated a heat load will inevitably appear. This heat load has to be taken care of in some way, usually with both the water-cooling and the lubrication system. Despite its name, one of the major tasks of the latter one is, to draw out heat from between lubricated surfaces. In contrast to the water cooling system, which is primarily designed for cooling the cylinder block, the lubrication system is mainly required for cooling the crankshaft and piston rod bearings. A lubrication system for today’s automotive engines consists of several components, i.e. an oil pump, a pressure relief valve and an oil filter. This study focuses on the dynamic characteristics of a pressure relief valve and how the system temperature is affected by the critical design parameters of the valve. Using a thermodynamic simulation model together with an optimisation strategy makes it possible to express the desired system characteristics. Then, the optimisation strategy seeks for a similar system configuration with help of the model.展开更多
文摘A local composition expression has been derived from the Guggenheim′s quasi-chemicalequation.On this basic a thermodynamic model,the quasi-chemical local composition model(QCLC)was established.To examine its capability for correlation and prediction,Baxter′s adhesivehard sphere mixtures were used,and an improved numerical method was proposed to estimate theirthermodynamic properties.By means of this method the excess properties of the mixtures composedof four kinds of adhesive hard spheres were calculated,The activity coefficients from QCLC modelwere compared with those from the Wilson,NRTL and UNIQUAC equations.Results show thatamong these models,the QCLC model is the best one for correlation and prediction.
文摘The mechanical losses in an internal combustion engine cause a significant decrease in the engine’s overall efficiency. Wherever friction work is dissipated a heat load will inevitably appear. This heat load has to be taken care of in some way, usually with both the water-cooling and the lubrication system. Despite its name, one of the major tasks of the latter one is, to draw out heat from between lubricated surfaces. In contrast to the water cooling system, which is primarily designed for cooling the cylinder block, the lubrication system is mainly required for cooling the crankshaft and piston rod bearings. A lubrication system for today’s automotive engines consists of several components, i.e. an oil pump, a pressure relief valve and an oil filter. This study focuses on the dynamic characteristics of a pressure relief valve and how the system temperature is affected by the critical design parameters of the valve. Using a thermodynamic simulation model together with an optimisation strategy makes it possible to express the desired system characteristics. Then, the optimisation strategy seeks for a similar system configuration with help of the model.
