Laboratory Experiments in Fluids and Propulsion Education

Author(s):  
Ray Taghavi

The advantages and requirements for propulsion laboratories in engineering schools is discussed. A typical propulsion laboratory set-up suitable for aircraft reciprocating and gas turbine engines is presented. Sample results of engine performance analysis from these laboratories will also be presented.

Author(s):  
B. Roth ◽  
J. de Luis

This paper presents and evaluates a lost thrust method for analysis of thermodynamic performance in gas turbine engines. This method is based on the definition of a hypothetical ideal engine that is used as a point of comparison to evaluate performance of the real engine. Specifically, component loss is quantified in terms of decrements in thrust of the real engine relative to the ideal engine having the same design point cycle. These lost thrust decrements provide a basis for accurately evaluating the performance cost of component losses while simultaneously accounting for all component interactions. The analysis algorithm is formally developed in detail and is then demonstrated for a typical separate flow turbofan engine. Various scenarios are examined and the results of these exercises are used to draw conclusions regarding the strengths and weaknesses of this approach to gas turbine performance analysis.


Author(s):  
P. A. Phillips ◽  
Peter Spear

After briefly summarizing worldwide automotive gas turbine activity, the paper analyses the power plant requirements of a wide range of vehicle applications in order to formulate the design criteria for acceptable vehicle gas turbines. Ample data are available on the thermodynamic merits of various gas turbine cycles; however, the low cost of its piston engine competitor tends to eliminate all but the simplest cycles from vehicle gas turbine considerations. In order to improve the part load fuel economy, some complexity is inevitable, but this is limited to the addition of a glass ceramic regenerator in the 150 b.h.p. engine which is described in some detail. The alternative further complications necessary to achieve satisfactory vehicle response at various power/weight ratios are examined. Further improvement in engine performance will come by increasing the maximum cycle temperature. This can be achieved at lower cost by the extension of the use of ceramics. The paper is intended to stimulate the design application of the gas turbine engine.


Author(s):  
Jeffrey S. Patterson ◽  
Soren K. Spring

The Landing Craft Air Cushion (LCAC) gas turbine engines operate in an extremely harsh environment and are exposed to excessive amounts of foreign contaminants. The present method of crank washing is effective when properly performed, but is labor intensive and increases craft downtime. Naval Ship Systems Engineering Station (NAVSSES) designed and installed a prototype on-line detergent wash system which reduced maintenance and craft downtime. Initial test results indicated that the system reduced engine performance degradation and corrosion.


Author(s):  
M. A. Monroe ◽  
A. H. Epstein ◽  
H. Kumakura ◽  
K. Isomura

The performance of a regenerated gas turbine generator in the 3–5 kW power range has been analyzed to understand why its measured efficiency was on the order of 6% rather than the 20% suggested by consideration of its components’ efficiencies as measured on rigs. This research suggests that this discrepancy can be primarily attributed to heat and fluid leaks not normally considered in the analysis of large gas turbine engines because they are not as important at large scale. In particular, fluid leaks among the components and heat leakage from the hot section into the compressor flow path contributed the largest debits to the engine performance. Such factors can become more important as the engine size is reduced. Other non-ideal effects reducing engine performance include temperature flow distortion at the entrance to both the compressor and turbine. A cycle calculation including all of the above effects matched measured engine data. It suggests that relatively simple changes such as thermal isolation and leak sealing can increase both power output and efficiency of this engine, over 225% in the latter case. The validity of this analysis was demonstrated on an engine in which partial thermal isolation and improved sealing resulted in a more than 40% increase in engine output power.


Author(s):  
Giovanni Torella

The influence of air system an engine performance and behaviour is considered. A method based on the polytropic efficiency concept has been developed in order to calculate the thermodynamic characteristics of air bleed. This method has been included in the “Design Point” and “Off Design” codes of different configuration engines. The paper shows the wide applications of the programs for several calculations. Moreover the results of the faults of air system are shown by both diagnostic and fault simulation computer programs.


2019 ◽  
pp. 39-44
Author(s):  
Stanislav Fábry ◽  
Miroslav Spodniak ◽  
Peter Gašparovič ◽  
Peter Koščák

The paper deals with testing of aircraft gas turbine engines. The main goal of the research is to propose and design testing sequence for a new or rebuilt engine. All factors and circumstances are described, including surroundings of the engine under test. Prerequisite knowledge is introduced, including the theory of testing, description of test beds, the methods of measurement of engine parameters and special factors that affect engine performance. Some examples of real testing facilities are mentioned. The result of the work is a proposal of test cycle, that can be modified according to engine purpose and specification.


Author(s):  
G. Torella

The possibility of the use of scaling factors in the calculations and in the simulation of gas turbine engines have been considered. Application of this technique to the simulation of trend analysis, the evaluation of the component maps shifting during the operational life of the engine and the calculation of matrices of influence have been presented. Moreover, some problems related to the use of scaling factors have been studied and their effects on the engine performance have been presented.


Author(s):  
Jason Cromarty ◽  
Sylvester Abanteriba

An experimental and theoretical investigation was undertaken to identify and evaluate the key technical issues surrounding the ‘drop-in’ utilisation of alternative bio-fuels in aviation gas-turbine propulsion systems. Region-suitable biofuels were identified and suitability evaluated based on the following three criteria: ‘drop-in’ capability, environmental and economic sustainability and industrialisation prospects. Bio-fuel engine performance will be evaluated based on the specific fuel consumption, specific thrust, nature and quantity of emissions through theoretical modelling. This paper outlines a variety of different bio-fuel type options that were investigated. By using engineering and scientific methodology the fuels were evaluated to verify their suitability for gas-turbine aviation use. The eventual bio-fuel selected for further evaluation was a locally produced mustard seed oil derivative bio-fuel which was blended at various blend ratios with standard Jet A-1 turbine fuel. Verification testing processes for future investigation are detailed. In addition to engine performance evaluation endeavours, this paper also seeks to address and offer recommendations in the areas of bio-fuel production, transport, storage, certification and emissions.


Author(s):  
A. Carelli

The experience acquired in developing an automotive gas-turbine engine is traced. Problems of design, construction, and development unique to a small gas-turbine engine and its application to an automobile are discussed. The engine performance and operational characteristics are then described. Finally, there is a discussion of the problems that must be solved before gas-turbine engines may successfully compete with reciprocating engines in automotive road transport.


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