Volume 4 Issue 5
Authors: Ahmed M. Rashad
Abstract: Evaluating the performance enhancement of a diesel engine through the addition of Oxy-hydrogen (HHO) gas generated through water electrolysis has been investigated by several researchers. The outcomes were claimed to be very promising. It is thought however that the results need more investigation. This study is carried out to evaluate the influence of adding HHO gas into the inlet air on the performance of a direct injection diesel engine. The experimental work is carried out under constant speed with varying load and amount of introduced HHO generated through water electrolysis. In this work the results contrary to many publication showed that, the thermal efficiency increases only at low loads and the brake specific fuel consumption consequently decreases at low loads too (up to 23% of maximum load). Using oxyhydrogen; the maximum engine power decreases with increasing electrolyte concentration. The maximum reduction in maximum power was (3.8 % to 7.6). An explanation for the results was attempted.
Keywords: Oxyhydrogen; Thermal Efficiency; Fuel Consumption
Authors: Chen Yang; Hangxing He; Li Zhao
Abstract: This paper describes a hybrid simulation work on waterwall system and combustion process of a 600 MW supercritical boiler with W-flame furnace. A nonlinear distributed mathematical model which can be applied to the real time dynamic simulation was performed for analysing the dynamic characteristics of the waterwall system under typical working condition in this paper. The purpose of the numerical calculations was to determine the distributions of the fluid temperature and other corresponding thermal physical parameters. Coupled with the obtained fluid temperature as the boundary condition, the computational fluid dynamics (CFD) simulation of the combustion characteristics for the 600 MW supercritical boiler with W-flame furnace was conducted. Conventional methods usually separated the CFD simulations from process simulations; our work achieved the coupling between these two kinds of simulation. Through the hybrid simulation of these two models, more accurate distribution characteristics and combustion characteristics were obtained. The results reflect good agreements with the in-situ operating status of the supercritical boiler, which are valuable in practical engineering. And this work will be helpful for further design and research of the dynamic characteristics of the supercritical once-through boiler.
Keywords: Supercritical Once-through Boiler; Distributed Parameter Model; W-flame Furnace; Hybrid Simulation