Modeling Thermal Effects on Performance of Small Gas Turbines

2015 ◽  
Author(s):  
W. P. J. Visser ◽  
I. D. Dountchev
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Gas Turbine ◽  
Thermal Effects ◽  
Gas Turbines ◽  
Engine Performance ◽  
Unmanned Aircraft ◽  
Transient Performance ◽  
Large Engine ◽  
Aircraft Propulsion

Gas turbines are applied at increasingly smaller scales for both aircraft propulsion and power generation. Recuperated turboshaft micro turbines below 30 kW are being developed at efficiencies competitive with other heat engines. The rapidly increasing number of unmanned aircraft applications requires the development of small efficient aircraft propulsion gas turbines. Thermal effects such as steady-state heat losses and transient heat soakage on large engine performance are relatively small and therefore often neglected in performance simulations. At small scales however, these become very significant due to the much higher heat transfer area-to-volume ratios in the gas path components. Recuperators often have high heat capacity and therefore affect transient performance significantly, also with large engine scales. As a result, for accurate steady-state and transient performance prediction of micro and recuperated gas turbines, thermal effects need to be included with sufficient fidelity. In the paper, a thermal network model functionality is presented that can be integrated in a gas turbine system simulation environment such as the Gas turbine Simulation Program GSP [1]. In addition, a 1-dimensional thermal effects model for recuperators is described. With these two elements, thermal effects in small recuperated gas turbines can be accurately predicted. Application examples are added demonstrating and validating the methods with models of a recuperated micro turbine. Simulation results are given predicting effects of heat transfer and heat loss on steady-state and transient performance.

scholarly journals The Effect of Heat Transfer on Gas Turbine Transients

1986 ◽  
Author(s):  
P. Pilidis ◽  
N. R. L. MacCallum
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Gas Turbine ◽  
Thermal Effects ◽  
Transient Performance ◽  
Adiabatic Flow ◽  
Boundary Layer Development ◽  
Layer Development

This paper describes how allowance for the thermal effects of non-adiabatic flow, altered boundary layer development, changes in tip clearances and changes in seal clearances have been incorporated into a general gas turbine transient program. These non-adiabatic effects have been investigated, modelling a two-spool bypass engine. The model has predicted events that occur in practice and also indicates which of the parameters are the most influential in the alteration of transient performance.

Design, Development and Application of Vehicle Gas Turbine Engines

1966 ◽  
Vol 181 (1) ◽  
pp. 149-172
Author(s):  
P. A. Phillips ◽  
Peter Spear
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Low Cost ◽  
Engine Performance ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Design Development ◽  
Turbine Engine ◽  
Wide Range ◽  
Cycle Temperature

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.

Research on Matching Characteristics of Ship-Engine-Propeller of COGAG

2021 ◽  
Author(s):  
Zhitao Wang ◽  
Jiayi Ma ◽  
Haichao Yu ◽  
Tielei Li
Keyword(s):  
Steady State ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Research Work ◽  
Simulation Models ◽  
Operating Characteristics ◽  
Modular Modeling ◽  
Steady State Operation ◽  
Pitch Ratio ◽  
Main Engine

Abstract The combined gas turbine and gas turbine power propulsion device (COGAG power propulsion device) is an advanced combined power system, which uses multiple gas turbines as the main engine to drive propellers to propel the ship. COGAG power propulsion device has high power density, excellent stability and maneuverability, it receives more and more attention in the field of ship power at home and abroad. This article takes the COGAG power propulsion device as the research object, uses simulation methods to study its steady-state operating characteristics, and conducts a ship-engine-propeller optimization matching analysis based on economy and maneuverability. The research work carried out in this article is as follows. Firstly, according to the structural relationship between the various components and the system thermal cycle mode of the COGAG power propulsion device, establish the controller, main engine, gear box, clutch, shafting, propeller, ship and other components and simulation models of the system with the modular modeling idea. Secondly, divide the gears according to ship speed. For the four working modes of single-gas turbine with load, dual-gas turbine with load, three-gas turbine with load, and four-gas turbine with load, analysis the ship-engine-propeller optimization matching of the COGAG power propulsion device based on economy and maneuverability, and calculate the best shaft speed and propeller pitch ratio in each gear, so as to obtain the steady-state operation characteristics of the COGAG power propulsion device based on the ship-engine-propeller matching, which provides a basis for determining the target parameters of the dynamic process.

A General Program for the Prediction of the Transient Performance of Gas Turbines

1985 ◽  
Author(s):  
P. Pilidis ◽  
N. R. L. Maccallum
Keyword(s):  
Mass Flow ◽  
Thermal Effects ◽  
Gas Turbines ◽  
Transient Performance ◽  
Prediction Program ◽  
Wide Range ◽  
General Program

The paper describes a general program which has been developed for the prediction of the transient performance of gas turbines. The program is based on the method of continuity of mass flow. It has been applied successfully to a wide range of aero gas turbines, ranging from single to three-spool and from simple jet to bypass types with or without mixed exhausts. The results for three of these engine types are illustrated. Computing times are reasonable, increasing with the complexity of the engine. A parallel paper describes the inclusion of thermal effects in the prediction program.

Some Effects of Size on the Performances of Small Gas Turbines

2003 ◽  
Author(s):  
C. Rodgers
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Engine Performance ◽  
Lessons Learned ◽  
Rapid Expansion ◽  
Cycle Performance ◽  
Frictional Drag ◽  
Component Design ◽  
Turbine Component ◽  
Performance Development

By the new millennia gas turbine technology standards the size of the first gas turbines of Von Ohain and Whittle would be considered small. Since those first pioneer achievements the sizes of gas turbines have diverged to unbelievable extremes. Large aircraft turbofans delivering the equivalent of 150 megawatts, and research micro engines designed for 20 watts. Microturbine generator sets rated from 2 to 200kW are penetrating the market to satisfy a rapid expansion use of electronic equipment. Tiny turbojets the size of a coca cola can are being flown in model aircraft applications. Shirt button sized gas turbines are now being researched intended to develop output powers below 0.5kW at rotational speeds in excess of 200 Krpm, where it is discussed that parasitic frictional drag and component heat transfer effects can significantly impact cycle performance. The demarcation zone between small and large gas turbines arbitrarily chosen in this treatise is rotational speeds of the order 100 Krpm, and above. This resurgence of impetus in the small gas turbine, beyond that witnessed some forty years ago for potential automobile applications, fostered this timely review of the small gas turbine, and a re-address of the question, what are the effects of size and clearances gaps on the performances of small gas turbines?. The possible resolution of this question lies in autopsy of the many small gas turbine component design constraints, aided by lessons learned in small engine performance development, which are the major topics of this paper.

Evaluation of Numerical Methods to Predict Temperature Distributions of an Experimentally Investigated Convection-Cooled Gas-Turbine Blade

2017 ◽  
Author(s):  
E. Findeisen ◽  
B. Woerz ◽  
M. Wieler ◽  
P. Jeschke ◽  
M. Rabs
Keyword(s):  
Heat Transfer ◽  
Numerical Methods ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Gas Turbines ◽  
Cooling System ◽  
Fe Model ◽  
Gas Turbine Blade ◽  
Transfer Coefficients ◽  
Temperature Distributions

This paper presents two different numerical methods to predict the thermal load of a convection-cooled gas-turbine blade under realistic operating temperature conditions. The subject of the investigation is a gas-turbine rotor blade equipped with an academic convection-cooling system and investigated at a cascade test-rig. It consists of three cooling channels, which are connected outside the blade, so allowing cooling air temperature measurements. Both methods use FE models to obtain the temperature distribution of the solid blade. The difference between these methods lies in the generation of the heat transfer coefficients along the cooling channel walls which serve as a boundary condition for the FE model. One method, referred to as the FEM1D method, uses empirical one-dimensional correlations known from the available literature. The other method, the FEM2D method, uses three-dimensional CFD simulations to obtain two-dimensional heat transfer coefficient distributions. The numerical results are compared to each other as well as to experimental data, so that the benefits and limitations of each method can be shown and validated. Overall, this paper provides an evaluation of the different methods which are used to predict temperature distributions in convection-cooled gas-turbines with regard to accuracy, numerical cost and the limitations of each method. The temperature profiles obtained in all methods generally show good agreement with the experiments. However, the more detailed methods produce more accurate results by causing higher numerical costs.

scholarly journals Comparison of Coriolis and Turbine Type Flow Meters for Fuel Measurement in Gas Turbine Testing

1993 ◽  
Author(s):  
J. D. MacLeod ◽  
W. Grabe
Keyword(s):  
Steady State ◽  
Gas Turbine ◽  
Mass Flow ◽  
Gas Turbines ◽  
Gas Turbine Engine ◽  
Turbine Engine ◽  
Turbine Flowmeter ◽  
Turbine Performance ◽  
Coriolis Flowmeter ◽  
Project Objectives

The Machinery and Engine Technology (MET) Program of the National Research Council of Canada (NRCC) has established a program for the evaluation of sensors to measure gas turbine engine performance accurately. The precise measurement of fuel flow is an essential part of steady-state gas turbine performance assessment. Prompted by an international engine testing and information exchange program, and a mandate to improve all aspects of gas turbine performance evaluation, the MET Laboratory has critically examined two types of fuel flowmeters, Coriolis and turbine. The two flowmeter types are different in that the Coriolis flowmeter measures mass flow directly, while the turbine flowmeter measures volumetric flow, which must be converted to mass flow for conventional performance analysis. The direct measurement of mass flow, using a Coriolis flowmeter, has many advantages in field testing of gas turbines, because it reduces the risk of errors resulting from the conversion process. Turbine flowmeters, on the other hand, have been regarded as an industry standard because they are compact, rugged, reliable, and relatively inexpensive. This paper describes the project objectives, the experimental installation, and the results of the comparison of the Coriolis and turbine type flowmeters in steady-state performance testing. Discussed are variations between the two types of flowmeters due to fuel characteristics, fuel handling equipment, acoustic and vibration interference and installation effects. Also included in this paper are estimations of measurement uncertainties for both types of flowmeters. Results indicate that the agreement between Coriolis and turbine type flowmeters is good over the entire steady-state operating range of a typical gas turbine engine. In some cases the repeatability of the Coriolis flowmeter is better than the manufacturers specification. Even a significant variation in fuel density (10%), and viscosity (300%), did not appear to compromise the ability of the Coriolis flowmeter to match the performance of the turbine flowmeter.

scholarly journals Impact of compressed air energy storage demands on gas turbine performance

2020 ◽  
pp. 095765092090627 ◽  
Author(s):  
Uyioghosa Igie ◽  
Marco Abbondanza ◽  
Artur Szymański ◽  
Theoklis Nikolaidis
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Engine Performance ◽  
Compressed Air ◽  
Design Stage ◽  
Simulation Code ◽  
Ratio Distribution ◽  
Stall Margin ◽  
Industrial Gas Turbines

Industrial gas turbines are now required to operate more flexibly as a result of incentives and priorities given to renewable forms of energy. This study considers the extraction of compressed air from the gas turbine; it is implemented to store heat energy at periods of a surplus power supply and the reinjection at peak demand. Using an in-house engine performance simulation code, extractions and injections are investigated for a range of flows and for varied rear stage bleeding locations. Inter-stage bleeding is seen to unload the stage of extraction towards choke, while loading the subsequent stages, pushing them towards stall. Extracting after the last stage is shown to be appropriate for a wider range of flows: up to 15% of the compressor inlet flow. Injecting in this location at high flows pushes the closest stage towards stall. The same effect is observed in all the stages but to a lesser magnitude. Up to 17.5% injection seems allowable before compressor stalls; however, a more conservative estimate is expected with higher fidelity models. The study also shows an increase in performance with a rise in flow injection. Varying the design stage pressure ratio distribution brought about an improvement in the stall margin utilized, only for high extraction.

Gas Turbine Fouling Offshore: Effective Online Water Wash Through High Water-to-Air Ratio

2018 ◽  
Vol 141 (4) ◽  
Author(s):  
Stian Madsen ◽  
Lars E. Bakken
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Peak Load ◽  
Engine Performance ◽  
High Water ◽  
Operational Experience ◽  
Successful Operation ◽  
Water Rate ◽  
Offshore Field ◽  
Key Parameter

Optimized operation of gas turbines is discussed for a fleet of 11 GE LM2500PE engines at a Statoil North Sea offshore field in Norway. Three engines are generator drivers, and eight engines are compressor drivers. Several of the compressor drive engines are running at peak load (T5.4 control), hence, the production rate is limited by the available power from these engines. The majority of the engines discussed run continuously without redundancy, hence, the gas turbine uptime is critical for the field's production and economy. The performance and operational experience with online water wash at high water-to-air ratio (w.a.r.), as well as successful operation at longer maintenance intervals and higher average engine performance are described. The water-to-air ratio is significantly increased compared to the original equipment manufacturer (OEM) limit (OEM limit is 17 l/min which yields approximately 0.5% water-to-air ratio). Today the engines are operated at a water rate of 50 l/min (three times the OEM limit) which yields a 1.4% water-to-air ratio. Such a high water-to-air ratio has been proven to be the key parameter for obtaining good online water wash effectiveness. Possible downsides of high water-to-air ratio have been thoroughly studied.

Experimental Identification of Steady-State Turbomachinery Heat Transfer Using Nondimensional Groups

2020 ◽  
Vol 142 (6) ◽  
Author(s):  
Markus Baumann ◽  
Christian Koch ◽  
Stephan Staudacher
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Gas Turbines ◽  
Experimental Identification ◽  
Wide Range ◽  
Nonsteady State ◽  
Data Points ◽  
Steady State Heat ◽  
Steady State Heat Transfer ◽  
Turboshaft Engine

Abstract Diabatic performance modeling is a prerequisite for engine condition monitoring based on nonsteady-state data points (e.g., Putz et al. 2017, “Jet Engine Gas Path Analysis Based on Takeoff Performance Snapshots,” ASME J. Eng. Gas Turbines Power, 139(11), p. 111201.). The importance of diabatic effects increases with decreasing engine size. Steady-state diabatic modeling of turbomachinery components is presented using nondimensional parameters derived from a dimensional analysis. The resulting heat transfer maps are approximated using the analytic solution for a pipe. Experimental identification of the maps requires the measurement of casing and gas path temperatures. This approach is demonstrated successfully using a small turboshaft engine as a test vehicle. A limited amount of measurements was needed to generate a steady-state heat transfer map which is valid for a wide range of operating points.

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