scholarly journals High Pressure Ratio Intercooled Turboprop Study

1992 ◽  
Author(s):  
C. Rodgers
Keyword(s):  
High Pressure ◽  
Gas Turbine ◽  
Waste Heat ◽  
Pressure Ratio ◽  
Weight Ratio ◽  
Unmanned Aircraft ◽  
High Pressure Ratio ◽  
Rotary Engines ◽  
Component Efficiency ◽  
Long Endurance

High altitude long endurance unmanned aircraft impose unique contraints on candidate engine propulsion systems and types. Piston, rotary and gas turbine engines have been proposed for such special applications. Of prime importance is the requirement for maximum thermal efficiency (minimum specific fuel consumption) with minimum waste heat rejection. Engine weight, although secondary to fuel economy, must be evaluated when comparing various engine candidates. Weight can be minimized by either high degrees of turbocharging with the piston and rotary engines, or by the high power density capabilities of the gas turbine. The design characteristics and features of a conceptual high pressure ratio intercooled turboprop are discussed. The intended application would be for long endurance aircraft flying at an altitude of 60,000 ft. (18,300 m). It is estimated that such a turboprop would be capable of thermal efficiencies exceeding 40% with current state-of-the-art component efficiency levels and an overall compressor pressure ratio of 66.0. Projected Power (at altitude) to weight ratio is comparable to that of competitive piston and rotary engines.

Turbines and Structures for Ultra-High Pressure Ratio Aero-Engines

2016 ◽  
Author(s):  
Anders Lundbladh ◽  
Ralf von der Bank ◽  
Richard Avellán ◽  
Stefan Forsman ◽  
Stefan Donnerhack ◽  
...  
Keyword(s):  
High Pressure ◽  
Direct Reduction ◽  
Pressure Ratio ◽  
Weight Ratio ◽  
Performance Improvements ◽  
High Pressure Ratio ◽  
Ultra High Pressure ◽  
Component Efficiency ◽  
Aero Engines ◽  
Emission Core

This paper describes the research carried out in the European Commission co-funded project LEMCOTEC (Low Emission Core Engine Technology) on aerodynamics for turbines and structures for compressors, combustors and turbines. The aim is to significantly contribute to the reduction of the environmental footprint of aviation with regard to emissions from aero engines. The LEMCOTEC turbine and structure technologies are directed primarily to act as enablers for higher thermal efficiency arising from increased overall pressure ratio. Thus the work is supporting increased operating temperatures, reduced core deformation, reduced cooling flows and increased performance to weight ratio, in addition to direct reduction of flow losses and associated component efficiency increases. The article details the targets for performance improvements, the validation of the technologies and how they, together with LEMCOTEC’s improved technologies on compressors and combustors, relate to the goal of building ultra-high pressure ratio engines.

scholarly journals The Thermodynamic Design of a Combined Steam and Gas Turbine Marine Propulsion System

1967 ◽  
Author(s):  
R. M. Marwood ◽  
C. A. Bassilakis
Keyword(s):  
High Pressure ◽  
Gas Turbine ◽  
Waste Heat ◽  
Pressure Ratio ◽  
Heating System ◽  
Waste Heat Boiler ◽  
High Pressure Ratio ◽  
Operating Modes ◽  
Marine Propulsion ◽  
Marine Diesel

The subject of this paper is the thermodynamic design of a 25,000 shp combined steam and gas turbine (COGAS) powerplant for marine propulsion. The plant includes a high-pressure ratio, aircraft-type gas turbine which exhausts into an unfired, low-pressure waste-heat boiler. The paper considers all aspects of the thermodynamic design including selection of the feed heating system, steam conditions, and gas turbine cycle. It considers the different part-throttle operating modes, and describes the major components and machinery arrangements. It is shown that the efficiency of this relatively simple, state-of-the-art system equals or exceeds that of high-pressure marine steam plants, and approaches the efficiency (based on effective horsepower at the propeller) of the low-speed marine diesel.

Design Study of an Advanced Concept Simple Gas Turbine for Possible Use in Low Emission Automobiles

1972 ◽  
Author(s):  
H. C. Eatock ◽  
M. D. Stoten
Keyword(s):  
High Pressure ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Simple Cycle ◽  
Turbine Engines ◽  
Nox Emissions ◽  
Preliminary Design ◽  
Gas Turbine Engines ◽  
High Pressure Ratio

United Aircraft Corporation studied the potential costs of various possible gas turbine engines which might be used to reduce automobile exhaust emissions. As part of that study, United Aircraft of Canada undertook the preliminary design and performance analysis of high-pressure-ratio nonregenerated (simple cycle) gas turbine engines. For the first time, high levels of single-stage component efficiency are available extending from a pressure ratio less than 4 up to 10 or 12 to 1. As a result, the study showed that the simple-cycle engine may provide satisfactory running costs with significantly lower manufacturing costs and NOx emissions than a regenerated engine. In this paper some features of the preliminary design of both single-shaft and a free power turbine version of this engine are examined. The major component technology assumptions, in particular the high pressure ratio centrifugal compressor, employed for performance extrapolation are explained and compared with current technology. The potential low NOx emissions of the simple-cycle gas turbine compared to regenerative or recuperative gas turbines is discussed. Finally, some of the problems which might be encountered in using this totally different power plant for the conventional automobile are identified.

A Performance Autopsy of Three Centrifugal Compressors for a Small Gas Turbine

2010 ◽  
Author(s):  
Colin Rodgers ◽  
Dan Brown
Keyword(s):  
High Pressure ◽  
Gas Turbine ◽  
Radial Flow ◽  
Pressure Ratio ◽  
Test Results ◽  
Design Features ◽  
Centrifugal Compressors ◽  
High Pressure Ratio ◽  
Flow Type ◽  
The One

Three 140mm tip diameter centrifugal compressors were designed and tested to determine the one exhibiting the best performance most suitable for eventual application to a small 60KW radial flow type gas turbine. The design features, and stage test results of these three moderately high pressure ratio impellers are presented, together with a comparison of their respective test and CFD computed performance maps.

Effects of Reynolds number on the performance of a high pressure-ratio turbocharger compressor

2013 ◽  
Vol 56 (6) ◽  
pp. 1361-1369 ◽  
Author(s):  
XinQian Zheng ◽  
Yun Lin ◽  
BinLin Gan ◽  
WeiLin Zhuge ◽  
YangJun Zhang
Keyword(s):  
Reynolds Number ◽  
High Pressure ◽  
Pressure Ratio ◽  
High Pressure Ratio

Effect of Recirculation Device With Counter Swirl Vane on Performance of High Pressure Ratio Centrifugal Compressor

2011 ◽  
Author(s):  
Hideaki Tamaki
Keyword(s):  
High Pressure ◽  
Mach Number ◽  
Flow Rate ◽  
Centrifugal Compressor ◽  
Pressure Ratio ◽  
Negative Slope ◽  
Tip Leakage Flow ◽  
Recirculation Flow ◽  
Operating Range ◽  
High Pressure Ratio

Centrifugal compressors used for turbochargers need to achieve a wide operating range. The author has developed a high pressure ratio centrifugal compressor with pressure ratio 5.7 for a marine use turbocharger. In order to enhance operating range, two different types of recirculation devices were applied. One is a conventional recirculation device. The other is a new one. The conventional recirculation device consists of an upstream slot, bleed slot and the annular cavity which connects both slots. The new recirculation device has vanes installed in the cavity. These vanes were designed to provide recirculation flow with negative preswirl at the impeller inlet, a swirl counterwise to the impeller rotational direction. The benefits of the application of both of the recirculation devices were ensured. The new device in particular, shifted surge line to a lower flow rate compared to the conventional device. This paper discusses how the new recirculation device affects the flow field in the above transonic centrifugal compressor by using steady 3-D calculations. Since the conventional recirculation device injects the flow with positive preswirl at the impeller inlet, the major difference between the conventional and new recirculation device is the direction of preswirl that the recirculation flow brings to the impeller inlet. This study focuses on two effects which preswirl of the recirculation flow will generate. (1) Additional work transfer from impeller to fluid. (2) Increase or decrease of relative Mach number. Negative preswirl increases work transfer from the impeller to fluid as the flow rate reduces. It increases negative slope on pressure ratio characteristics. Hence the recirculation flow with negative preswirl will contribute to stability of the compressor. Negative preswirl also increases the relative Mach number at the impeller inlet. It moves shock downstream compared to the conventional recirculation device. It leads to the suppression of the extension of blockage due to the interaction of shock with tip leakage flow.

scholarly journals The Design and Evaluation of a High Pressure Ratio Radial Turbine

1992 ◽  
Author(s):  
K. R. Pullen ◽  
N. C. Baines ◽  
S. H. Hill
Keyword(s):  
High Pressure ◽  
High Speed ◽  
Pressure Ratio ◽  
Performance Measurements ◽  
Turbine Engine ◽  
High Pressure Ratio ◽  
Turbine Efficiency ◽  
Wide Range ◽  
Dimensional Parameters ◽  
Very High

A single stage, high speed, high pressure ratio radial inflow turbine was designed for a single shaft gas turbine engine in the 200 kW power range. A model turbine has been tested in a cold rig facility with correct simulation of the important non-dimensional parameters. Performance measurements over a wide range of operation were made, together with extensive volute and exhaust traverses, so that gas velocities and incidence and deviation angles could be deduced. The turbine efficiency was lower than expected at all but the lowest speed. The rotor incidence and exit swirl angles, as obtained from the rig test data, were very similar to the design assumptions. However, evidence was found of a region of separation in the nozzle vane passages, presumably caused by a very high curvature in the endwall just upstream of the vane leading edges. The effects of such a separation are shown to be consistent with the observed performance.

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