Performance of diesel engines in association with variable geometry turbomachines.

Abstract

The investigations described in this thesis can be divided into three main topics. They are as follows: (i) Variable geometry turbocharging (ii) Differential compound engine (iii) differential gas turbine. In each cash the overall performance chartacteristics are investigated in detail, and in particular o timum operating schedules for variable geometry turbines and compressors are metermined. The variable geometry turbocharging and differential was turbine studies are purely theoretical, whilst the differential compound engine study is supported by a substantial body of experimental results.(i) VARIABLE GEOMETRY TURBOCHARGING This project was a theoretical investigation of variable geometry tur ocharging, with reference to high speed, medium power Diesel engines. The project was sponsored by the ilitary vehicles Engineering Establishment of the Ministry of Defence. Various components of a tur ocharged Diesel engine unit were theoretically modelled for a digital computer, and the performance of the unit was predicted under various operating conditions. A preliminary theoretical investigation was carried out with a jerkins T 6.354 Diesel engine fitted with a Holset 3Mp turbccharger. These investigations were carried out under two main headings: (a) Fixed inlet prerwhirl for the compressor and variable inlet nozzle angles for the turbine. (b) Variable inlet prewhirl I'or the compressor and variable inlet nozzle angles for the turbine. A similar investigation was carried out for the case of a proposed Rolls-Royce CV-8 Diesel engine fitted with a pair of Holset 4MD turbochargers. (ii) DIFFERENTIAL COMPOUND ENGINE extensive experimental work was carried out on the Differential Compound Engine unit using the lerkins T 6.354 engine. This unit was the subject of an earlier investigation, when powered by a Rootes TS 3 engine. A computer program - as developed to predict the performance of the unit, under various operating conditions. (iii) DIFFERENTIAL GAS TURBINE A basic theoretical investigation was carried out on a differential gas turbine scheme using radial turbomachines. Suitable radial turbines and compressors were selected to model a differential gas turbine unit capable of producing about 200 Hi at design point. A computer program was developed to predict the performance of the unit, under various operating conditions. The main theme running through all the above investigations is the use of variable geometry turbomachinery to obtain improved operating flexibility.

Date of Award	1975
Original language	English
Awarding Institution	University of Bath