Numerical simulation study on the thermal environment in heading face

Based on κ-ε turbulence model, the distributions of the velocity field, tempera- ture field, thermal comfort index, PMV-PPD （Predicted Mean Vote-Predicted Percentage Dissatisfied）, and air quality index, mean age of air were obtained of Zhouyuanshan Coal Mine in -650 m level of a heading face by CFD（Computational Fluid Dynamics）software, Airpak 2.0. Moreover, the human thermal comfort and the air quality of the heading face were analyzed with PMV-PPD and mean age of air indices, which received an intuitive visualization and accurate evaluation results. In order to create a safe, comfortable, and economical underground operating environment, a scientific, rational, and comprehensive prediction and evaluation needed to provide a theoretical and technical basis for coal mine ventilation, cooling, heat harm treatment, and prevention. Meanwhile, from the human thermal comfort and air quality to research the underground environment, it embodied the concept of being human oriented.

Experimental investigation into the effects of Argemone biodiesel/diesel blends on cyclic variations in a multi-cylinder CRDI engine

Internal combustion engines suffer from high cyclic variations that result in higher emissions,lower efficiency,higher fuel consump-tion and poor drivability.The purpose of this study is to investigate how Argemone mexicana biodiesel(AGB)/diesel blended fuels affect the cyclic variability of combustion parameters such as maximum cylinder pressure(Pmax)and indicated mean effective pressure(IMEP)in a four-cylinder turbocharged intercooled common-rail direct injection engine under various engine loading conditions.The chemical and physical properties of AGB produced from A.mexicana oil were measured and compared according to the ASTM D6751 standards.In various volumetric ratios,AGB and diesel fuel were blended as D100,AB10(10%AGB+90%D100),AB20(20%AGB+80%D100)and AB30(30%AGB+70%D100).The IMEP and Pmax time-series data were collected over 200 consecutive cycles at low,partial and high engine loads at a constant engine speed of 2000 rpm.The coefficients of variation(COV)of combustion parameters(Pmax and IMEP)were measured for different AGB/diesel blends and found to be within acceptable limits.The results show that COV_(Pmax) and COV_(IMEP) decrease as the engine load increases.It was observed that at low load,AB10 has the lowest COV(Pmax,IMEP),and at partial and high load,AB20 has the lowest COV(Pmax,IMEP)among all the blends.