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

Author(s):  
H. C. Eatock ◽  
M. D. Stoten

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.

1970 ◽  
Author(s):  
N. K. H. Scholz

The effect of the main design parameters of the aero gas turbine engine cycle, namely combustion temperature and compression pressure ratio, on the specific performance values is discussed. The resulting development trend has been of essential influence on the technology. Relevant approaches are outlined. The efforts relating to weight and manufacturing expense are also indicated. In the design of aero gas turbine engines increasing consideration is given to the specific flight mission requirements, such as for instance by the introduction of the by-pass principle. Therefore direct application of aero gas turbine engines for ship propulsion without considerable modifications, as has been practiced in the past, is not considered very promising for the future. Nevertheless, there are possibilities to take advantage of aero gas turbine engine developments for ship propulsion systems. Appropriate approaches are discussed. With the experience obtained from aero gas turbine engines that will enter service in the early seventies it should be possible to develop marine gas turbine engines achieving consumptions and lifes that are competitive with those of advanced diesel units.


Author(s):  
K.-L. Tzuoo ◽  
S. S. Hingorani ◽  
A. K. Sehra

Recent trend toward lightweight, compact compression systems for advanced aircraft gas turbine engines has created a need for very high pressure ratio fan and compressor stages. One way of achieving pressure ratio in excess of 3:1 in an axial blade row is to introduce splitters (partial vanes) between the principal blades, a concept pioneered by Wennerstrom during early 70s for application in a 3:1 pressure ratio single axial stage. This paper presents an advanced methodology for high pressure ratio splittered rotor design. The methodology centers around combining a meridional flow calculation, an arbitrary meanline blade generation procedure, and 3-D inviscid and viscous analyses. Methods for specifying work distribution, solidity, loss, and deviation distributions, as well as the airfoil generation and splitter vane placement are discussed in detail. Importance of 3-D viscous effects along with results from a 3-D viscous calculation for Wennerstrom’s splittered rotor are also presented.


Author(s):  
Matthew B. Rivera ◽  
Randall D. Manteufel

A current issue with high-pressure-ratio compressors found in aircraft engines is the temperature of the air exiting the compressor. The exiting air is used as coolant for engine components found in later stages of the engine such as first-stage turbine blades, and afterburner walls. A viable option for reducing outlet temperature of high-pressure-ratio compressors is to “bleed-off” a fraction of the air which is cooled in a heat exchanger by rejecting heat into the liquid fuel stream and then use the air for cooling critical components downstream. Bleeding off air from the outlet of the compressor has two benefits: (1) air temperature is reduced, and (2) fuel temperature is elevated. Along with reduced air temperatures, the fuel will ultimately receive the heat lost from the air, making the fuel more ideal for combustion purposes. The higher temperature the fuel is received in the combustion process, the greater the work output will be according to the basics of thermodynamic combustion. The objective of this case study is to optimize the efficiency of the cross-flow micro channel heat exchanger, with respect to (1) volume (1.75–2.75 mm3) and heat transfer, and (2) weight (0.15–.25 N) and heat transfer. The optimization of the heat exchanger will be evaluated within the bounds of the 2nd law of thermodynamics (exergy). The only effective way to measure the 2nd law of thermodynamics is through exergy destruction or its equivalent form: entropy generation as a factor of dead state temperature. With relations and equations obtained to design an optimal heat exchanger, applications to high performance aircraft gas turbine engines is considered through exergy. The importance of developing an exergetic analysis for a thermal system is highly effective for identifying area’s within the system that have the path of highest resistance to work potential through various modes of heat transfer and pressure loss. Thus, optimization to reduce exergy destruction is sought after through this design method alongside verifying other heat exchanger methods through effectiveness.


Author(s):  
Thomas L. Ragland

With the increasing need for more efficient industrial gas turbine engines, the recuperated engine cycle is being considered as a means of meeting these needs. This paper discusses a recuperated cycle design that is optimized to take full advantage of the recuperator but at the same time accommodate the real world market constraints of reliability, durability and cost. Current simple cycle industrial engines are evolving to very high pressure ratios and high firing temperatures in order to reach cycle efficiencies in the 37% to 39% range. Some simple cycle industrial gas turbines with lower cycle pressure ratios and firing temperatures have been modified so a recuperated option can be added. Although the addition of a recuperator to these engines does improve cycle efficiency, levels of only the 33% to 35% range are reached. This is mainly due to the fact that the resulting cycles are not optimized for a recuperator. An engine cycle that is optimized around a recuperator could obtain cycle efficiencies in the 43% to 45% range. Fortunately, this cycle optimizes at low pressure ratios and modest firing temperatures which results in lower cost components which tend to offset the additional cost of the recuperator.


Author(s):  
A. V. Soudarev ◽  
A. A. Souryaninov ◽  
V. Yu. Tikhoplav ◽  
S. I. Kozlov

Gas turbine engines have been widely applied to pipeline systems to drive pumping equipment (gas compressors, oil pumps, etc) and electric generators. Thus, there are over 4000 units involved into the gas industry operation in Russia. Nearly 90% of machines of around 60 models are running as gas pumping units. E.g. eight types of gas turbine engines of power ranging 1 500 to 4 300 KW are operated at the electric stations to supply electric power for gas pipeline’s own needs (ONS). The bulk (over 30%) of the standard units were designed during the 60s of the past century and, therefore, their efficiency is rather low (23–28%) with the running time mounting to 60 000–80 000 hours. A good number of the existing units do not meet the international norms in terms of admissible toxic emissions (NOx, CO, etc). At the same time, the state of the basic hardware (casing, rotors, bearings, combustors, heat exchangers, etc) is, in fact, not bad, i.e. all these devices and systems could operate for, at least, 100 thousand hours more. This is an industrially well matured and thoroughly mastered, reparable and relatively inexpensive equipment. Therefore, it is of a real practical interest to implement an upgrade of the “old” machines which would allow provision of both using the existing hardware under standard operating conditions and their efficiency increasing (by 6–10% abs) and the NOx emissions reduction (up to 12.5–37.5 ppm) and CO emissions (up to 50 ppm). The like upgrade could be put into effect on the basis of integration of the existing turbomachines of gas pumping units or ONS and the ceramic overstructure — a high pressure unit. The Research–Engineering “Ceramic Heat Engines” Center (NIZ KTD) jointly with the JSC “Proletarsky Works” (St. Petersburg) has developed an ONS gas turbine drive on the base of the 1.5 MW gas turbine engine with a high temperature ceramic overstructure made as a high pressure turbocompressor with a lox-toxic combustor installed between its compressor and turbine. As a result of such modification, a pilot GTE was produced with the initial gas temperature of 1050°C instead of 827°C but of the same power and with the efficiency of 28% instead of 22%, the NOx emissions being 12.5 ppm instead of 50 ppm. The main design modifications of the base-line engine first and foremost were linked with the standard compressor (4 last stages are envisaged to be removed) and the combustor. The independent high pressure unit, at the same time, must be designed and manufactured anew. Given an effective small-size ceramic airheater is applied, you can increase its initial gas temperature (up to 1350°C with the GTE efficiency increased up to 42–47%.


Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4214
Author(s):  
Kranthi Kumar Maniam ◽  
Shiladitya Paul

The increased demand for high performance gas turbine engines has resulted in a continuous search for new base materials and coatings. With the significant developments in nickel-based superalloys, the quest for developments related to thermal barrier coating (TBC) systems is increasing rapidly and is considered a key area of research. Of key importance are the processing routes that can provide the required coating properties when applied on engine components with complex shapes, such as turbine vanes, blades, etc. Despite significant research and development in the coating systems, the scope of electrodeposition as a potential alternative to the conventional methods of producing bond coats has only been realised to a limited extent. Additionally, their effectiveness in prolonging the alloys’ lifetime is not well understood. This review summarises the work on electrodeposition as a coating development method for application in high temperature alloys for gas turbine engines and discusses the progress in the coatings that combine electrodeposition and other processes to achieve desired bond coats. The overall aim of this review is to emphasise the role of electrodeposition as a potential cost-effective alternative to produce bond coats. Besides, the developments in the electrodeposition of aluminium from ionic liquids for potential applications in gas turbines and the nuclear sector, as well as cost considerations and future challenges, are reviewed with the crucial raw materials’ current and future savings scenarios in mind.


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.


1978 ◽  
Vol 100 (4) ◽  
pp. 640-646 ◽  
Author(s):  
P. Donovan ◽  
T. Cackette

A set of factors which reduces the variability due to ambient conditions of the hydrocarbon, carbon monoxide, and oxides of nitrogen emission indices has been developed. These factors can be used to correct an emission index to reference day ambient conditions. The correction factors, which vary with engine rated pressure ratio for NOx and idle pressure ratio for HC and CO, can be applied to a wide range of current technology gas turbine engines. The factors are a function of only the combustor inlet temperature and ambient humidity.


Author(s):  
C. P. Lea˜o ◽  
S. F. C. F. Teixeira ◽  
A. M. Silva ◽  
M. L. Nunes ◽  
L. A. S. B. Martins

In recent years, gas-turbine engines have undergone major improvements both in efficiency and cost reductions. Several inexpensive models are available in the range of 30 to 250 kWe, with electrical efficiencies already approaching 30%, due to the use of a basic air-compressor associated to an internal air pre-heater. Gas-turbine engines offer significant advantages over Diesel or IC engines, particularly when Natural Gas (NG) is used as fuel. With the current market trends toward Distributed Generation (DG) and the increased substitution of boilers by NG-fuelled cogeneration installations for CO2 emissions reduction, small-scale gas turbine units can be the ideal solution for energy systems located in urban areas. A numerical optimization method was applied to a small-scale unit delivering 100 kW of power and 0.86 kg/s of water, heated from 318 to 353K. In this academic study, the unit is based on a micro gas-turbine and includes an internal pre-heater, typical of these low pressure-ratio turbines, and an external heat recovery system. The problem was formulated as a non-linear optimisation model with the minimisation of costs subject to the physical and thermodynamic constraints. Despite difficulties in obtaining data for some of the components cost-equations, the preliminary results indicate that the optimal compressor pressure ratio is about half of the usual values found in large installations, but higher than those of the currently available micro-turbine models, while the turbine inlet temperature remains virtually unchanged.


Author(s):  
Yoshiharu Tsujikawa ◽  
Makoto Nagaoka

This paper is devoted to the analyses and optimization of simple and sophisticated cycles, particularly for various gas turbine engines and aero-engines (including scramjet engine) to achive the maximum performance. The optimization of such criteria as thermal efficiency, specific output and total performance for gas turbine engines, and overall efficiency, non-dimensional thrust and specific impulse for aero-engines have been performed by the optimization procedure with multiplier method. The comparisons of results with analytical solutions establishes the validity of the optimization procedure.


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