A Comparison of Mixed Convection Heat Transfer in Upward Stepped Tilted Constant Area Pipe between Air and Diesel Exhausted Gas

摘要

The widespread diesel engines usage has many advantages, such as electricity generating units with 500 kVA and above, which mainly takes a great attention in countries and places suffering from a large lack of daily supplying electricity. These may need to about 12 units to cover one populated kilometer. These engines play an important role in environmental pollution problems all over the world. Pollutions generated from exhaust emissions are the main responsible factor for environmental pollutions, and they lead to many problems of health. Many policies have been imposed worldwide in recent years to reduce negative effects of diesel engine emissions on human health and environment. Many research efforts have been carried out on both diesel exhaust pollutant emissions and aftertreatment emission control technologies. The aftertreatment systems convert the pollutant gases separately into non-pollutant compounds. Studies show that its function depends on exhaust gas temperature and velocity. This paper deals with a comparison of laminar mixed heat transfer in circular different inclination pipe with 0, 45 and 90 degrees angle between fresh air and diesel exhaust gas (DEG). They are examined at a constant heat flux of 115 and 816 W-m~(-2) for 450 and 2008 Reynolds numbers. The results show a clear increase in temperature distribution and a clear decrease in local Nusselt number grow with the exhaust gas pipe inclination increase. This will help to modify the aftertreatment design parameters, their inclination and more generally the most important a trial to solve such environmental problem.