Turbopump Design: Comparison of Numerical Simulations to an Already Validated Reduced-Order Model

The article expands on the ongoing assessment of the reduced order model proposed by some of the authors for the geometric definition and noncavitating performance evaluation in the preliminary design and parametric optimization of mixed-flow centrifugal turbopumps. Some of the dynamically most significant predictions of the model are compared with the experimentally validated URANS (Unsteady Reynolds-Averaged Navier-Stokes) simulations of the non-cavitating flow through a typical six-bladed unshrouded mixed-flow turbopump for liquid propellant rocket engines operating at both design and off-design flow conditions and different values of the impeller clearance. The observed discrepancies can be explained in terms of the simplifying assumptions introduced for the development of the model and their relative magnitude (< ±10%) does not adversely interfere with the accurate prediction of the turbopump performance over a wide range of operating conditions above and below design flow rate. Together with earlier experimental validations, the results dramatically confirm the capability of the proposed model to generate useful engineering solutions of the turbopump preliminary design problem at a negligible fraction of the computational cost required by 3D numerical simulations.