PERFORMANCE OF A FOUR STROKE ADIABATIC DI DIESEL ENGINE
Extensive research is going on in the area of improvement of the engine thermal efficiency. In diesel engines approximately only one-third of the fuel energy is converted into useful work and major part of the energy is lost to cooling water. In an adiabatic engine (or insulated engine), the energy loss through cooling system is avoided by applying a layer of insulating material over the walls of the combustion chamber. The commonly used insulating materials are ceramic coatings such as silicon nitride, silicon carbide, zirconia (zirconium oxide) etc. As per the literature the partially Stabilized Zarconium (PSZ) is quite useful for the adiabatic engine application because of its excellent insulating characteristics, adequate strength and thermal expansion characteristics. Further this improves fuel economy, reduces, emissions and further reduces noise due to a lower rate of pressure rise. In the present investigations an adiabatic engine is developed with air gap insulation over the piston and cylinder liner, PSZ coated cylinder head and valves. With the higher temperatures in the combustion chambers in an adiabatic engine, widely available low cetane fuels like alcohols (which have high latent heat of vaporization) can also be burnt so that the ever-increasing demand for imported diesel can be reduced. In the present investigations a computer program has been developed in C language for an insulated engine and with that the theoretical results are obtained and then the same thing is compared with experimental results of adiabatic engine.
Computer Simulation of an LHR DI Diesel Engine
The effect on engine performance of insulating combustion chambers was simulated for a turbocharged direct injection diesel engine. We developed a low heat rejection (LHR) diesel cycle simulation. It includes a gas flow model, a heat transfer model, and a two zone combustion model. In the heat transfer model, convective and radiation heat transfer between the gas and walls was computed, taking into account the combustion chamber surface temperature swings
Laminar heat or mass transfer in rectangular channels and in cylindrical tubes for fully developed flow: comparison of solutions obtained for various boundary conditions
Abstract A comparison is made of results obtained with various boundary conditions at the wall of the channels. By comparing blood Sherwood numbers for finite wall resistance with those for constant concentration boundary condition only a small variation is found for various points along the blood channel.