Modeling of Thermal Cycle CI Engine with Multi-Stage Fuel Injection

This work presents a complete thermal cycle modeling of a four-stroke diesel engine with a three-dimensional simulation program CFD - AVL Fire. The object of the simulation was the S320 Andoria engine. The purpose of the study was to determine the effect of fuel dose distribution on selected parameters of the combustion process. As a result of the modeling, time spatial pressure distributions, rate of pressure increase, heat release rate and NO and soot emission were obtained for 3 injection strategies: no division, one pilot dose and one main dose and two pilot doses and one main dose. It has been found that the use of pilot doses on the one hand reduces engine hardness and lowers NO emissions and on the other hand, increases soot emissions

Eksperimentalna raziskava in matematični model toplotne prehodnosti dvokapnega solarnega destilatorja

n this study, a double slope solar still has been designed and fabricated with the help of locally available materials for the climatic condition of Sultanpur, India. The experimental study was performed to investigate the effect of basin water, wind velocity on the heat transfer coefficient (convective, evaporative, and radiative) and yield of solar still. A mathematical model is developed to understand the impact of wind velocity and basin water depth in the double slope solar still on the heat transfer coefficient. It was found that the convective heat transfer coefficient depends upon the water mass and the temperature of basin mass, and glass cover temperature. The maximum value of hew (55.05 W/(m2K) and 31.80 W/(m2K)) and hcw , (2.48 W/(m2K) and 2.38 W/(m2K)) found for depths of 2 cm and 5 cm, respectively. The radiative heat transfer coefficient found to be a maximum of 8.31 W/(m2K) for 2 cm depth, and it increases as the condensation increases, because the glass surface temperature increases as vapour transfers its energy to the surface. On increasing the depth from 2 cm to 5 cm, the yield from the solar still decreases by 25.45 %. The maximum yield of 2.5 l/m2/day was found for a 2 cm water depth. The theoretical and experimental yield agreed with an error of 7.5 %, 3.25 %, 7.4 %, and 8.4 % for water depths of 2 cm, 3 cm, 4 cm, and 5 cm, respectively. It was also found that the yield from the solar still increases as the wind speed increase because this leads the faster condensation at the glass surface

Modeling of Thermal Cycle CI Engine with Multi-Stage Fuel Injection

This work presents a complete thermal cycle modeling of a four-stroke diesel engine with a three-dimensional simulation program CFD - AVL Fire. The object of the simulation was the S320 Andoria engine. The purpose of the study was to determine the effect of fuel dose distribution on selected parameters of the combustion process. As a result of the modeling, time spatial pressure distributions, rate of pressure increase, heat release rate and NO and soot emission were obtained for 3 injection strategies: no division, one pilot dose and one main dose and two pilot doses and one main dose. It has been found that the use of pilot doses on the one hand reduces engine hardness and lowers NO emissions and on the other hand, increases soot emissions

Numerična analiza sistema dvostopenjskega ejektorja-difuzorja na osnovi konstantne hitrosti sprememb kinetične energije

Supersonic ejector energy flow devices are extensively used in various applications, such as pumping, mixing, compression, etc. The conventional single-stage ejector (SSE) design approaches are inefficient for modelling an efficient ejector because of their inefficiency in minimizing mixing losses in the mixing chamber, thermodynamic shock in constant area diffuser, and utilization of redundant discharged momentum at the exit of the first stage. The physics-based single-stage ejector design has better solutions because it minimizes irreversibility due to thermodynamic shocks. The present study utilizes the constant rate of a kinetic energy change physics-based approach to design a two-stage ejector (TSE) for water vapour. The computational fluid dynamics (CFD) tool ANSYS-Fluent has been utilized to predict flow characteristics. The performance of the ejector-diffuser system has also been compared with a single-stage ejector. It is found that the performance of TSE is 70 % higher than that of the performance of SSE