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The effect of inlet and exhaust manifold pressures on the scavenging and fluid flow inside a turbocharged, carbureted, uniflow scavenged two-stroke engine has been studied numerically. An axisymmetric computational code, CARE, has been used for the purpose. The inlet pressure is varied between 0.25 MPa and 0.29 MPa, keeping exhaust pressure constant at 0.23904 MPa, to study the effect of inlet pressure. Similarly, the exhaust pressure is varied between 0.2 MPa and 0.25 MPa, keeping inlet pressure constant at 0.26104 MPa. The results are plotted in the form of velocity vector plots, fresh charge concentration contours and swirl velocity contours to illustrate the flow field at various crank angles. The global quantities, viz., the cylinder pressure, total mass of gases in the cylinder, fresh charge and residual gas masses in the cylinder during scavenging are plotted as functions of crank angle, for various values of the inlet and exhaust pressures.

Multidimensional prediction of the scavenging characteristics of a homogeneous charge uniflow scavenged two-stroke cycle engine has been carried out. An engine geometry having the same dimensions as the General Motors EMD 710 engine has been analyzed. A multidimensional computer program, CARE, has been developed for this purpose. The fluid flow problem is subdivided into its global and local parts and the two parts are solved simultaneously. Flow is assumed to be axisymmetric. Turbulence is modelled by a zero-equation eddy viscosity model. Combustion is treated as a stoichiometric heat release phenomenon. The simulation is repeated over many cycles of the crank to achieve a periodicity in the results obtained. This computer program is used to study the effects of port/valve sizes and timings on the scavenging characteristics of the engine, given that the pressures at the inlet and exhaust ports are held constant.