Analysis of the Error in the Gas Temperature and the Thermocouple Time Constant Measuring Through Gas Turbine Engine Tests

Author(s):  
Sergiy V. Yepifanov ◽  
Qijie Li
Author(s):  
Godwin Ita Ekong ◽  
Christopher A. Long ◽  
Peter R. N. Childs

Compressor tip clearance for a gas turbine engine application is the radial gap between the stationary compressor casing and the rotating blades. The gap varies significantly during different operating conditions of the engine due to centrifugal forces on the rotor and differential thermal expansions in the discs and casing. The tip clearance in the axial flow compressor of modern commercial civil aero-engines is of significance in terms of both mechanical integrity and performance. In general, the clearance is of critical importance to civil airline operators and their customers alike because as the clearance between the compressor blade tips and the casing increases, the aerodynamic efficiency will decrease and therefore the specific fuel consumption and operating costs will increase. This paper reports on the development of a range of concepts and their evaluation for the reduction and control of tip clearance in H.P. compressors using an enhanced heat transfer coefficient approach. This would lead to improvement in cruise tip clearances. A test facility has been developed for the study at the University of Sussex, incorporating a rotor and an inner shaft scaled down from a Rolls-Royce Trent aero-engine to a ratio of 0.7:1 with a rotational speed of up to 10000 rpm. The idle and maximum take-off conditions in the square cycle correspond to in-cavity rotational Reynolds numbers of 3.1×106 ≤ Reφ ≤ 1.0×107. The project involved modelling of the experimental facilities, to demonstrate proof of concept. The analysis shows that increasing the thermal response of the high pressure compressor (HPC) drum of a gas turbine engine assembly will reduce the drum time constant, thereby reducing the re-slam characteristics of the drum causing a reduction in the cold build clearance (CBC), and hence the reduction in cruise clearance. A further reduction can be achieved by introducing radial inflow into the drum cavity to further increase the disc heat transfer coefficient in the cavity; hence a further reduction in disc drum time constant.


Author(s):  
Karl F. Prigge ◽  
Jerry W. Watts ◽  
Terrence E. Dwan

A multi-input, multi-output (MIMO) controller for an advanced gas turbine has been developed and tested using a computer simulation. The engine modeled is a two-and-one half spool gas turbine with both an intercooler and a regenerator. In addition, variable stator vanes are present in the free-power turbine. This advanced engine is proposed for future naval propulsion for both mechanical drive ships and electrical drive ships. The designed controller controls free-power turbine speed and turbine inlet temperature using fuel flow and angle of the stator vanes. The controller will also have four modes of operation to deal with over temperature and over speed conditions. An eight state reduced order controller was used with pole placement and LQR to arrive at control gains. Both these methods required considerable insight into the problem. This insight was provided by previous experience with controller design for a less complicated engine, and also by use of a polyhedral search model of the gas turbine engine. The difficulty with a MIMO controller was that both inputs affect both of the control variables. The classical resolution of this problem is to have one input control one variable at a fast time constant and the other input control the other variable at a slow time constant. The “optimal” resolution of this problem is analyzed using the transient curves and basic control theory.


2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Mustagime Tülin Yildirim ◽  
Bülent Kurt

Modern condition monitoring-based methods are used to reduce maintenance costs, increase aircraft safety, and reduce fuel consumption. In the literature, parameters such as engine fan speeds, vibration, oil pressure, oil temperature, exhaust gas temperature (EGT), and fuel flow are used to determine performance deterioration in gas turbine engines. In this study, a new model was developed to get information about the gas turbine engine’s condition. For this model, multiple regression analysis was carried out to determine the effect of the flight parameters on the EGT parameter and the artificial neural network (ANN) method was used in the identification of EGT parameter. At the end of the study, a network that predicts the EGT parameter with the smallest margin of error has been developed. An interface for instant monitoring of the status of the aircraft engine has been designed in MATLAB Simulink. Any performance degradation that may occur in the aircraft’s gas turbine engine can be easily detected graphically or by the engine performance deterioration value. Also, it has been indicated that it could be a new indicator that informs the pilots in the event of a fault in the sensor of the EGT parameter that they monitor while flying.


Author(s):  
C. A. Fucinari ◽  
J. K. Vallance ◽  
C. J. Rahnke

The design and development of the regenerator seals used in the AGT101 gas turbine engine are described in this paper. The all ceramic AGT101 gas turbine engine was designed for 100 hp at 5:1 pressure ratio with 2500F (1371C) turbine inlet temperature. Six distinct phases of seal design were investigated experimentally and analytically to develop the final design. Static and dynamic test rig results obtained during the seal development program are presented. In addition, analytical techniques are described. The program objectives of reduced seal leakage, without additional diaphragm cooling, to 3.6% of total engine airflow and higher seal operating temperature resulting from the 2000F (1093C) inlet exhaust gas temperature were met.


1980 ◽  
Author(s):  
N. T. Campbell ◽  
R. H. Groth ◽  
V. A. Zaccardi

Current technology and practices at Pratt & Whitney Aircraft Group, Commercial Products Division (P& WA) for monitoring gas turbine engine emissions as a function of engine operating parameters, fuels, and environmental factors are discussed from sampling procedures through final data reduction. Mobile laboratories and fixed systems are used to rapidly measure smoke, hydrocarbons, oxygen, oxides of nitrogen, water, carbon monoxide and carbon dioxide content. Calibration gases, traceable to the National Bureau of Standards (NBS), are provided by an in-house calibration laboratory. The data collected are fed into a computer to calculate emission factors, concentration levels, and when requested, gas temperature from the measured emissions. Problem areas, including an overall assessment of measurement accuracy, are discussed.


Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6570
Author(s):  
Iman K. Reksowardojo ◽  
Long H. Duong ◽  
Rais Zain ◽  
Firman Hartono ◽  
Septhian Marno ◽  
...  

Biofuels as alternative fuels in today’s world are becoming increasingly important for the reduction of greenhouse gases. Here, we present and evaluate the potential of a new alternative fuel based on the conversion of medium-chain fatty acids to biojet (MBJ), which was produced from coconut oil using hydrotreated processes. MBJ is produced by using both deoxygenation and isomerization processes. Several blends of this type of biojet fuel with Jet A-1 were run in a gas-turbine engine (Rover 1S/60, ROTAX LTD., London, England) for the purpose of investigating engine performance and emissions. Performance results showed almost the same results as those of Jet A-1 fuel for these fuels in terms of thermal efficiency, brake-specific fuel consumption, turbine-inlet temperature, and exhaust-gas temperature. The results of exhaust-gas emissions also showed no significant effects on carbon monoxide, unburned hydrocarbon, and nitrogen oxides, while a decrease in smoke opacity was found when blending MBJ with Jet A-1. MBJ performed well in both performance and emissions tests when run in this engine. Thus, MBJ brings hope for the development of aviation biofuels in tropical regions that have an abundance of bioresources, but are limited in technology and investment capital.


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