The selection and design of a power system for any form of underwater vehicle is an extremely complex and difficult task. The system must be capable of providing the vehicle with the required mission performance in terms of power and energy and also be volumetrically and gravimetrically compact.
When the vehicle to be used is a newly designed U.S. Navy Diver Propulsion Vehicle (DPV), other power system constraints are highlighted. These constraints include limited vehicle diameter, high performance operation, low power requirements, safety and a non-magnetic signature. Of the many power systems available, very few can fulfil the design criteria for the DPV. One system that can is the hydrocarbon fuelled Stirling engine — a dynamic heat engine using an external combustion system.
This paper describes the design of the combustion system for the Stirling engine powered DPV. Details are given of the design evaluation and the development of a combustion gas recirculation system to enable pure gaseous oxygen to be used as the combustion oxidant In addition, details are given of the restrictions imposed on component design and manufacture by the low vehicle power requirements.