Design of a silicon microfabricated rocket engine turbopump

Abstract

The advances in silicon microfabrication technology suggest the feasibility of high-precision mechanical devices for power conversion. This thesis describes the design of a silicon demonstration turbopump for a micro-rocket engine, and the analysis and experimental investigation of liquid bearings that may be implemented in a future turbopump. Liquid micro-scale lubrication is investigated. Models are developed to predict the performance of hydrostatic liquid thrust bearings, and hydrostatic and hydrodynamic liquid journal bearings. These models suggest that liquid operation of the existing micro-bearing rig is feasible. This device was tested with water to assess the bearings performance. The maximum speed achieved was 21,000 revolutions per minute, and was limited by the drag in this device designed for gas operation. A micro-scale turbopump producing a pressure rise of 30 atm for water was designed, as a demonstration of this concept for fluid pressurization in the rocket engine system. This thesis addresses several of the key design trades and identifies the fundamental engineering issues. This micropump integrates high-speed turbomachinery and micro-gas bearings. An innovative arrangement is proposed with coplanar pump and turbine for ease of fabrication and reduction of imbalance.