Design optimization of a scroll compressor

Includes bibliographical references (pages [69]-70).A strong demand for higher efficiency compressors that meet the stringent requirements of small size, light weight and quiet operation has resulted in the development of the scroll compressor. A scroll compressor’s pressure ratio is defined solely by the geometry of the scroll wraps. The equations for the involute profiles are established and the volume of the pockets are derived to illustrate the relationship between the various parameters. The relationships for the axial, radial, and tangential components of gas pressure forces, centrifugal force, bearing frictional forces, and contact forces are presented to quantify the system behavior. Optimization process has been employed as a tool to systematize the engineering design. The optimum design of the scroll compressor is formulated as a measure of performance parameters to be optimized while satisfying all the problem constraints. The system is mathematically defined in terms of the design variables, three objective functions (radius, mass of the orbiting scroll, and average torque to drive the compressor) and constraint equations representing the relationships within the design problem. Sensitivity analysis was performed on the design variables to determine their significance in the optimum design of the system. A multicriterion optimization of the scroll compressor was performed by considering the various objective functions simultaneously and assigning weighting coefficients to each objective function The relative size of the weighting coefficients reflect the relative importance of the various objective functions in the composite function.M.S. (Master of Science