scholarly journals Optimum Peak Cycle Pressure for the Intercooled-Supercharged Gas Turbine Engine

1995 ◽  
Author(s):  
Lin-Shu Wang ◽  
Lili Pan
Keyword(s):  
Gas Turbine ◽  
Thermal Efficiency ◽  
Pressure Ratio ◽  
Optimization Procedure ◽  
Simple Cycle ◽  
Specific Power ◽  
Turbine Engine ◽  
Performance Curves ◽  
Pressure Maximum ◽  
Cycle Temperature

Performance (thermal efficiency and mass specific power) of a simple-cycle gas turbine increases monotonically with peak cycle temperatures, for a given peak cycle temperature, the performance also depends on cycle pressure ratio or peak cycle pressure: maximum performance (both mass specific power and thermal efficiency near their maximum values) is achieved in a narrow range of optimum peak cycle pressures. A recently proposed intercooled-supercharged cycle gas turbine differs from the conventional intercooled cycle gas turbine in their intercooler placement. This paper studies the performance of the proposed cycle based on a reformulated intercooling-supercharging optimization procedure. The intercooler placement is defined by a new parameter, the intercooling supercharging parameter. In terms of the intercooling supercharging parameter and the peak cycle pressure, a map of performance curves (efficiency versus specific power) is constructed, which discloses a higher performance zone for the proposed cycle. This performance zone is defined by optimal intercooler placement and peak cycle pressures that are considerably higher than the simple-cycle’s optimum peak cycle pressures. At these higher pressures, the intercooled-supercharged-cycle gas turbine can achieve a new level of performance: a 20% to 30% improvement over the simple cycle in thermal efficiency and mass specific power.

scholarly journals The Effect of Blade Angle Design Selection on Wave-Turbine Engine Performance

1996 ◽  
Author(s):  
William E. Lear ◽  
Robert P. Kielb
Keyword(s):  
Gas Turbine ◽  
Pressure Ratio ◽  
Engine Performance ◽  
Expansion Ratio ◽  
Specific Power ◽  
Nasa Lewis Research ◽  
Substantial Impact ◽  
Turbine Engine ◽  
Wave Rotors ◽  
Cycle Temperature

Wave rotors have been investigated over several decades in part due to their potential for increasing the maximum cycle temperature in gas turbine engines via their self-cooling mechanism. Recent activities in this field have centered on the experiments and CFD design tools developed at NASA Lewis Research Center. Because of the fundamental objectives of that program, the work to date has concentrated on wave rotors rather than wave turbines. Wave turbines differ from wave rotors in that the flow passages are curved, similar to conventional turbines, so that the unit produces net shaft power. The purpose of this paper is to present an analysis technique which is used to quantify the substantial impact which blade curvature has on the maximum gas expansion ratio, and hence on the maximum cycle temperature. Limited optimization of the overall pressure ratio allows the maximum specific power and the corresponding efficiency to be found as a function of wave turbine inlet and exit blade angles and Mach number. A potential increase in specific power of 69% and a 6.8 percentage point increase in thermal efficiency over a conventional gas-turbine engine can be achieved through the use of a wave turbine.

Effects of Water and Steam Injection on Thermodynamic Performance of Gas-Turbine Systems

2011 ◽  
Vol 110-116 ◽  
pp. 2109-2116 ◽  
Author(s):  
Kyoung Hoon Kim
Keyword(s):  
Gas Turbine ◽  
Thermal Efficiency ◽  
Pressure Ratio ◽  
Steam Injection ◽  
Specific Power ◽  
Co2 Gas ◽  
Thermodynamic Performance ◽  
System Variables ◽  
Important System ◽  
Injection Ratio

The water and steam injection gas-turbine systems are comparatively investigated. Thermodynamic performances of the regenerative after-fogging gas-turbine (RAF) system, steam-injection gas-turbine (STIG) system, and the regenerative steam-injection gas-turbine (RSTIG) system are analyzed parametrically. Using the analytic model, the important system variables such as thermal efficiency, fuel consumption, specific power, and specific emission of CO2 gas are evaluated in terms of pressure ratio and water or steam injection ratio. The numerical results show that water or steam injection results in a notable enhancement of thermal efficiency and specific power.

Wave-Rotor Pressure-Gain Combustion Analysis for Power Generation and Gas Turbine Applications

2012 ◽  
Author(s):  
Manikanda Rajagopal ◽  
Abdullah Karimi ◽  
Razi Nalim
Keyword(s):  
Gas Turbine ◽  
Pressure Ratio ◽  
Turbulent Flame ◽  
Pressure Rise ◽  
Gas Turbine Engine ◽  
Operating Conditions ◽  
Specific Power ◽  
Inlet Temperature ◽  
Wave Rotor ◽  
Turbine Engine

A wave-rotor pressure-gain combustor (WRPGC) ideally provides constant-volume combustion and enables a gas turbine engine to operate on the Humphrey-Atkinson cycle. It exploits pressure (both compression and expansion) waves and confined propagating combustion to achieve pressure rise inside the combustor. This study first presents thermodynamic cycle analysis to illustrate the improvements of a gas turbine engine possible with a wave rotor combustor. Thereafter, non-steady reacting simulations are used to examine features and characteristics of a combustor rig that reproduces key features of a WRPGC. In the thermodynamic analysis, performance parameters such as thermal efficiency and specific power are estimated for different operating conditions (compressor pressure ratio and turbine inlet temperature). The performance of the WRPGC is compared with the conventional unrecuperated and recuperated engines that operates on the Brayton cycle. Fuel consumption may be reduced substantially with WRPGC introduction, while concomitantly boosting power. Simulations have been performed of the ignition of propane by a hot gas jet and subsequent turbulent flame propagation and shock-flame interaction.

Performance Analysis of Regenerative Steam Injection Gas Turbine (RSTIG) Systems

2003 ◽  
Author(s):  
Kousuke Nishida ◽  
Toshimi Takagi ◽  
Shinichi Kinoshita
Keyword(s):  
Power Generation ◽  
Gas Turbine ◽  
Thermal Efficiency ◽  
Pressure Ratio ◽  
Water Injection ◽  
Steam Injection ◽  
Specific Power ◽  
Small Scale ◽  
Total Efficiency ◽  
Optimum Pressure

There is a demand for developments of a distributed energy system using a small scale gas turbine. The steam injection configurations can improve the performances of the simple and regenerative gas turbine cycles. In this study, the thermal efficiency and exergy loss of two types of regenerative steam injection gas turbine (RSTIG) system are analyzed, and the performances of them are compared with those of the regenerative, water injection and STIG systems. It is noted that the optimum pressure ratio of the RSTIG systems becomes relatively low. The thermal efficiency of the RSTIG systems is higher than that of the water injection and STIG systems. The specific power of them is larger than that of the regenerative cycle. The steam injection configurations can be applied to the flexible heat and power generation system. The total efficiency of the heat and power generation of the RSTIG systems reaches more than 70% (HHV).

scholarly journals The WISC Gas Turbine Engine

1997 ◽  
Author(s):  
A. Radey Shouman ◽  
A. R. Shouman
Keyword(s):  
Heat Exchanger ◽  
Gas Turbine ◽  
Thermal Efficiency ◽  
Heat Recovery ◽  
Gas Turbine Engine ◽  
Specific Power ◽  
Turbine Engine ◽  
Basic Engine ◽  
Exhaust Heat ◽  
Exhaust Heat Recovery

Combined gas turbine-steam turbine cycles have gained widespread acceptance as the most efficient utilization of the gas turbine for power generation, particularly for large power plants. In order to maximize the achievable thermal efficiency, more than one exhaust heat recovery boiler is used. The current trend is to use three boilers at three different operating pressures, which improves thermal efficiency but significantly increases the initial cost of the plant. There are advantages in replacing an exhaust heat recovery system using multiple boilers by a single heat exchanger in which the water side pressure is above the critical pressure of water; we shall refer to such a heat exchanger as a supercritical heat exchanger. The supercritical steam leaving the heat exchanger is expanded in a two phase turbine and then fed into the engine combustor. A condenser and a water treatment system are used to recover most of the water in the exhaust stream. A turbine system identical to the basic engine turbine system is added in parallel in order to allow for the operation with increased mass flow due to the steam injection. To achieve maximum efficiency such a turbine should be provided with variable area nozzles. With this arrangement, it becomes possible to inject sufficient steam to produce stoichiometric combustion at the desired turbine inlet temperature. We shall refer to this cycle as the Water Injected Stoichiometric Combustion (WISC) gas turbine cycle. The various components described above can be added to any existing gas turbine engine to change it to the WISC configuration. The WISC engine offers significant economical advantages. The specific power output per pound of air for the WISC engine is more than five times that of the basic engine, the thermal efficiency is 75% higher than that of the basic engine. This produces a significant reduction in the initial investment in the plant as well as its operating expenses.

Performance Enhancement of a Gas Turbine With Humid Air and Utilization of LNG Cold Energy

1998 ◽  
Author(s):  
C. H. Song ◽  
S. T. Ro
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Power Efficiency ◽  
Performance Enhancement ◽  
Pressure Ratio ◽  
Simple Cycle ◽  
Cycle Performance ◽  
Specific Power ◽  
Humid Air ◽  
Cold Energy

It is well known that a cycle performance can be improved considerably by adopting humid air to a simple gas turbine. Further improvement can be achieved by utilizing LNG (liquified natural gas) cold energy which is obtained during vaporization process of natural gas from liquid to gas state. Qualitatively well known fact of high specific power and improvement of efficiency are analyzed quantitatively for various cases. These include comparisons of power, efficiency and other important operating parameters for the cases of a simple cycle and HAT cycle with and without utilization of LNG cold energy. Compared with simple cycle, HAT cycle got 48% increase in total work, 16% increase in efficiency and HAT-LNG cycle got each 54%, 17% increases at 10 pressure ratio. An analysis shows that a reasonable matching exists between the amount of LNG as fuel and the energy required to control inlet air temperature. It should be also admitted that use of a high cost liquified natural gas is inevitable for transportation of fuel from production site to consumer.

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.

Second Law Efficiency of an Intercooled-Reheated-Regenerative-Brayton Cycle With Variable Temperature Heat Reservoirs

2012 ◽  
Author(s):  
Vishal Anand ◽  
Krishna Nelanti ◽  
Kamlesh G. Gujar
Keyword(s):  
Gas Turbine ◽  
Variable Temperature ◽  
Pressure Ratio ◽  
Working Fluid ◽  
Thermodynamic Efficiency ◽  
Second Law ◽  
Brayton Cycle ◽  
Cooling Fluid ◽  
Turbine Engine ◽  
Temperature Heat

The gas turbine engine works on the principle of the Brayton Cycle. One of the ways to improve the efficiency of the gas turbine is to make changes in the Brayton Cycle. In the present study, Brayton Cycle with intercooling, reheating and regeneration with variable temperature heat reservoirs is considered. Instead of the usual thermodynamic efficiency, the Second law efficiency, defined on the basis of lost work, has been taken as a parameter to study the deviation of the irreversible Brayton Cycle from the ideal cycle. The Second law efficiency of the Brayton Cycle has been found as a function of reheat and intercooling pressure ratios, total pressure ratio, intercooler, regenerator and reheater effectiveness, hot and cold side heat exchanger effectiveness, turbine and compressor efficiency and heating capacities of the heating fluid, the cooling fluid and the working fluid (air). The variation of the Second law efficiency with all these parameters has been presented. From the results, it can be seen that the Second law efficiency first increases and then decreases with increase in intercooling pressure ratio and increases with increase in reheating pressure ratio. The results show that the Second law efficiency is a very good indicator of the amount of irreversibility of the cycle.

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