CHEN 3101 Chapter Notes - Chapter 9: Mach Number, Compressible Flow, Mass Flow Rate
Document Summary
Reciprocating internal combustion engines are usually used in cars: spark-ignition engine. Combustion of fuel is ignited by spark. Lighter and cheaper good for automobiles: compression-ignition engine. Creates high pressure and temperature that enable spontaneous combustion. Produces larger amount of power good for ships, buses . Mean effective pressure (mep) is the theoretical constant pressure that, if acted on the piston during power stroke, produces same net work as by one cycle. The work and heat transfer in each process can be represented as: note: w12/m is positive, representing work input; q41/m is positive, represent heat rejected. Thermal efficiency of the engine is the ratio of net work to net heat added: The specific internal energy can be expressed as: r = compression ratio, vr versus temperature can be found in table a-22 or a-22e in the textbook. When otto cycle is analyzed on a cold air-standard basis, the equations become:
