For quenching heat treatment process, mechanical agitation by impeller may provide better performance at a lower energy cost.  Efficient heat transfer in an impeller agitation system can be achieved by the proper placement of impeller in the quench tank as well as the proper selection of impeller type and geometry.  In this research, the fluid dynamics simulation has been employed to study the pumping capacity of 3-bladed axial flow impellers with various blade geometries for quenching applications.  The performances of various impellers are compared in terms of pumping flow number and power number.