Pulsed Impingement Turbine Cooling and Its Effect on the Efficiency of Gas Turbines With Pressure Gain Combustion

2021 ◽  
Vol 143 (7) ◽  
Author(s):  
Nicolai Neumann ◽  
Arne Berthold ◽  
Frank Haucke ◽  
Dieter Peitsch ◽  
Panagiotis Stathopoulos
Keyword(s):  
Gas Turbine ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Turbine Blades ◽  
Impingement Cooling ◽  
Turbine Cooling ◽  
Pressure Gain Combustion ◽  
Cooling Air ◽  
Gas Turbine Cycle ◽  
Cycle Efficiency

Abstract Performance improvements of conventional gas turbines are becoming increasingly difficult and costly to achieve. Pressure gain combustion (PGC) has emerged as a promising technology in this respect, due to the higher thermal efficiency of the respective ideal gas turbine cycle. Previous cycle analyses considering turbine cooling methods have shown that the application of pressure gain combustion may require more turbine cooling air. This has a direct impact on the cycle efficiency and reduces the possible efficiency gain that can potentially be harvested from the new combustion technology. Novel cooling techniques could unlock an existing potential for a further increase in efficiency. Such a novel turbine cooling approach is the application of pulsed impingement jets inside the turbine blades. In the first part of this paper, results of pulsed impingement cooling experiments on a curved plate are presented. The potential of this novel cooling approach to increase the convective heat transfer in the inner side of turbine blades is quantified. The second part of this paper presents a gas turbine cycle analysis where the improved cooling approach is incorporated in the cooling air calculation. The effect of pulsed impingement cooling on the overall cycle efficiency is shown for both Joule and PGC cycles. In contrast to the authors’ anticipation, the results suggest that for relevant thermodynamic cycles pulsed impingement cooling increases the thermal efficiency of Joule cycles more significantly than it does in the case of PGC cycles. Thermal efficiency improvements of 1.0 p.p. for pure convective cooling and 0.5 p.p. for combined convective and film with TBC are observed for Joule cycles. But just up to 0.5 p.p. for pure convective cooling and 0.3 p.p. for combined convective and film cooling with TBC are recorded for PGC cycles.

Pulsed Impingement Turbine Cooling and its Effect on the Efficiency of Gas Turbines With Pressure Gain Combustion

2020 ◽  
Author(s):  
Nicolai Neumann ◽  
Dieter Peitsch ◽  
Arne Berthold ◽  
Frank Haucke ◽  
Panagiotis Stathopoulos
Keyword(s):  
Gas Turbine ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Turbine Blades ◽  
Impingement Cooling ◽  
Turbine Cooling ◽  
Pressure Gain Combustion ◽  
Cooling Air ◽  
Gas Turbine Cycle ◽  
Cycle Efficiency

Abstract Performance improvements of conventional gas turbines are becoming increasingly difficult and costly to achieve. Pressure Gain Combustion (PGC) has emerged as a promising technology in this respect, due to the higher thermal efficiency of the respective ideal gas turbine cycle. Previous cycle analyses considering turbine cooling methods have shown that the application of pressure gain combustion may require more turbine cooling air. This has a direct impact on the cycle efficiency and reduces the possible efficiency gain that can potentially be harvested from the new combustion technology. Novel cooling techniques could unlock an existing potential for a further increase in efficiency. Such a novel turbine cooling approach is the application of pulsed impingement jets inside the turbine blades. In the first part of this paper, results of pulsed impingement cooling experiments on a curved plate are presented. The potential of this novel cooling approach to increase the convective heat transfer in the inner side of turbine blades is quantified. The second part of this paper presents a gas turbine cycle analysis where the improved cooling approach is incorporated in the cooling air calculation. The effect of pulsed impingement cooling on the overall cycle efficiency is shown for both Joule and PGC cycles. In contrast to the authors’ anticipation, the results suggest that for relevant thermodynamic cycles pulsed impingement cooling increases the thermal efficiency of Joule cycles more significantly than it does in the case of PGC cycles. Thermal efficiency improvements of 1.0 p.p. for pure convective cooling and 0.5 p.p. for combined convective and film with TBC are observed for Joule cycles. But just up to 0.5 p.p. for pure convective cooling and 0.3 p.p. for combined convective and film cooling with TBC are recorded for PGC cycles.

scholarly journals Potentials for Pressure Gain Combustion in Advanced Gas Turbine Cycles

2019 ◽  
Vol 9 (16) ◽  
pp. 3211
Author(s):  
Nicolai Neumann ◽  
Dieter Peitsch
Keyword(s):  
Gas Turbine ◽  
Thermal Efficiency ◽  
Specific Work ◽  
Turbine Cooling ◽  
Turbine Efficiency ◽  
Optimization Study ◽  
Pressure Gain Combustion ◽  
Reduce Emissions ◽  
Secondary Air ◽  
Gas Turbine Cycle

Pressure gain combustion evokes great interest as it promises to increase significantly gas turbine efficiency and reduce emissions. This also applies to advanced thermodynamic cycles with heat exchangers for intercooling and recuperation. These cycles are superior to the classic Brayton cycle and deliver higher specific work and/or thermal efficiency. The combination of this revolutionary type of combustion in an intercooled or recuperated gas turbine cycle can, however, lead to even higher efficiency or specific work. The research of these potentials is the topic of the presented paper. For that purpose, different gas turbine setups for intercooling, recuperation, and combined intercooling and recuperation are modeled in a gas turbine performance code. A secondary air system for turbine cooling is incorporated, as well as a blade temperature evaluation. The pressure gain combustion is represented by analytical-algebraic and empirical models from the literature. Key gas turbine specifications are then subject to a comprehensive optimization study, in order to identify the design with the highest thermal efficiency. The results indicate that the combination of intercooling and pressure gain combustion creates synergies. The thermal efficiency is increased by 10 percentage points compared to a conventional gas turbine with isobaric combustion.

scholarly journals A gas turbine cooled-stage expansion model for the simulation of blade cooling effects on cycle performance

2019 ◽  
Author(s):  
Roberta Masci ◽  
Enrico Sciubba
Keyword(s):  
Gas Turbine ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Numerical Procedure ◽  
Expansion Ratio ◽  
Cycle Performance ◽  
Inlet Temperature ◽  
Cooling Effects ◽  
Cooling Air ◽  
Cycle Efficiency

Modern gas turbines firing temperatures (1500-2000K) are well beyond the maximum allowable blade material temperatures. Continuous safe operation is made possible by cooling the HP turbine first stages -nozzle vanes and rotor blades- with a portion of the compressor discharge air, a practice that induces a penalty on the cycle thermal efficiency. Therefore, a current issue is to investigate the real advantage, technical and economical, of raising maximum temperatures much further beyond current values. In this paper, process simulations of a gas turbine are performed to assess HP turbine first-stage cooling effects on cycle performance. A new simplified and properly streamlined model is proposed for the non-adiabatic expansion of the hot gas mixed with the cooling air within the blade passage, which allows for a comparison of several cycle configurations at different TIT (turbine inlet temperature) and max (total turbine expansion ratio) with a realistically acceptable degree of approximation.. The calculations suggest that, at a given max, the TIT can be increased in order to reach higher cycle efficiency up to a limit imposed by the required amount and temperature of the cooling air. Beyond this limit, no significant gains in thermal efficiency are obtained by adopting higher max and/or increasing the TIT, so that it is convenient in terms of cycle performance to design at lower rather than higher max. The small penalty on cycle efficiency is compensated by lower plant cost. The results of our model agree with those of some previous much more complex and computationally expensive studies, so that the novelty of this paper lies in the original method adopted on which the proposed model is based, and in the fast, accurate and low resource intensity of the corresponding numerical procedure: all advantages that can be crucial for industry needs. The presented analysis is purely thermodynamic, with no investigation on the effects of the different configurations on plant costs, so that future work addressing a thermo-economic analysis of the air-cooled gas turbine power plant is the next logical step.

scholarly journals Three-dimensional optimal design of a cooled turbine considering the coolant-requirement change

Open Physics ◽  
2019 ◽  
Vol 17 (1) ◽  
pp. 768-778
Author(s):  
Wei Ba ◽  
Ziyuan Wang ◽  
Xuesong Li ◽  
Chunwei Gu
Keyword(s):  
Optimal Design ◽  
Gas Turbine ◽  
Turbine Blades ◽  
Three Dimensional ◽  
Aerodynamic Performance ◽  
Pressure Surface ◽  
Component Efficiency ◽  
Requirement Change ◽  
Cooling Air ◽  
Gas Turbine Cycle

Abstract Cooling technology is widely applied in modern turbines to protect the turbine blades, and extracting high-pressure cooling air from a compressor exerts a remarkable influence on the gas-turbine performance. However, the three-dimensional optimal design of a turbine in modern industrial practice is usually carried out by pursuing high component efficiency without considering possible changes in coolant requirement; hence, it may not exactly lead to improvement in the gas-turbine cycle efficiency. In this study, the turbine stator was twisted and leaned to achieve higher comprehensive efficiency, which is the cycle-based efficiency definition for a cooled turbine that considers both turbine aerodynamic performance and coolant requirement. First, the influence of twist and compound lean on turbine aerodynamic performance, considering stator-hub leakage, was investigated. Then, a method to predict the coolant requirement for turbines with different stator designs was applied, to evaluate coolant-requirement change at the design condition. The optimized turbines were finally compared to demonstrate the necessity of considering the coolant-requirement change in the optimal design. This indicated that proper twisting to open the throat area in the stator hub and compound lean to the pressure surface side could help improve the cooled-turbine comprehensive efficiency.

Advanced Gas Turbine and High Performance Gas-Steam Combined Cycle Plant With Blade Cooling Air Controlling

2006 ◽  
Author(s):  
Tadashi Tsuji
Keyword(s):  
Power Generation ◽  
Heat Exchanger ◽  
Gas Turbine ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Combined Cycle ◽  
Hot Water ◽  
Blade Cooling ◽  
Combined Cycle Plant ◽  
Cooling Air

Air cooling blades are usually applied to gas turbines as a basic specification. This blade cooling air is almost 20% of compressor suction air and it means that a great deal of compression load is not converted effectively to turbine power generation. This paper proposes the CCM (Cascade Cooling Module) system of turbine blade air line and the consequent improvement of power generation, which is achieved by the reduction of cooling air consumption with effective use of recovered heat. With this technology, current gas turbines (TIT: turbine inlet temperature: 1350°C) can be up-rated to have a relative high efficiency increase. The increase ratio has a potential to be equivalent to that of 1500°C Class GT/CC against 1350°C Class. The CCM system is designed to enable the reduction of blade cooling air consumption by the low air temperature of 15°C instead of the usual 200–400°C. It causes the turbine operating air to increase at the constant suction air condition, which results in the enhancement of power and thermal efficiency. The CCM is installed in the cooling air line and is composed of three stage coolers: steam generator/fuel preheater stage, heat exchanger stage for hot water supplying and cooler stage with chilled water. The coolant (chilled water) for downstream cooler is produced by an absorption refrigerator operated by the hot water of the upstream heat exchanger. The proposed CCM system requires the modification of cooling air flow network in the gas turbine but produces the direct effect on performance enhancement. When the CCM system is applied to a 700MW Class CC (Combined Cycle) plant (GT TIT: 135°C Class), it is expected that there will be a 40–80MW increase in power and +2–5% relative increase in thermal efficiency.

Influence of Steam Injection on Thermal Efficiency and Operating Temperature of GE-F5 Gas Turbines Applying VODOLEY System

2005 ◽  
Author(s):  
Mohsen Ghazikhani ◽  
Nima Manshoori ◽  
Davood Tafazoli
Keyword(s):  
Power Plant ◽  
Ambient Temperature ◽  
Gas Turbine ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Steam Injection ◽  
Gas Turbine Cycle

An industrial gas turbine has the characteristic that turbine output decreases on hot summer days when electricity demand peaks. For GE-F5 gas turbines of Mashad Power Plant when ambient temperature increases 1° C, compressor outlet temperature increases 1.13° C and turbine exhaust temperature increases 2.5° C. Also air mass flow rate decreases about 0.6 kg/sec when ambient temperature increases 1° C, so it is revealed that variations are more due to decreasing in the efficiency of compressor and less due to reduction in mass flow rate of air as ambient temperature increases in constant power output. The cycle efficiency of these GE-F5 gas turbines reduces 3 percent with increasing 50° C of ambient temperature, also the fuel consumption increases as ambient temperature increases for constant turbine work. These are also because of reducing in the compressor efficiency in high temperature ambient. Steam injection in gas turbines is a way to prevent a loss in performance of gas turbines caused by high ambient temperature and has been used for many years. VODOLEY system is a steam injection system, which is known as a self-sufficient one in steam production. The amount of water vapor in combustion products will become regenerated in a contact condenser and after passing through a heat recovery boiler is injected in the transition piece after combustion chamber. In this paper the influence of steam injection in Mashad Power Plant GE-F5 gas turbine parameters, applying VODOLEY system, is being observed. Results show that in this turbine, the turbine inlet temperature (T3) decreases in a range of 5 percent to 11 percent depending on ambient temperature, so the operating parameters in a gas turbine cycle equipped with VODOLEY system in 40° C of ambient temperature is the same as simple gas turbine cycle in 10° C of ambient temperature. Results show that the thermal efficiency increases up to 10 percent, but Back-Work ratio increases in a range of 15 percent to 30 percent. Also results show that although VODOLEY system has water treatment cost but by using this system the running cost will reduce up to 27 percent.

Application of “H Gas Turbine” Design Technology to Increase Thermal Efficiency and Output Capability of the Mitsubishi M701G2 Gas Turbine

2005 ◽  
Vol 127 (2) ◽  
pp. 369-374 ◽  
Author(s):  
Y. Fukuizumi ◽  
J. Masada ◽  
V. Kallianpur ◽  
Y. Iwasaki
Keyword(s):  
Gas Turbine ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Turbine Blades ◽  
Combined Cycle ◽  
Load Test ◽  
Air Cooling ◽  
Load Testing ◽  
Design Development

Mitsubishi completed design development and verification load testing of a steam-cooled M501H gas turbine at a combined cycle power plant at Takasago, Japan in 2001. Several advanced technologies were specifically developed in addition to the steam-cooled components consisting of the combustor, turbine blades, vanes, and the rotor. Some of the other key technologies consisted of an advanced compressor with a pressure ratio of 25:1, active clearance control, and advanced seal technology. Prior to the M501H, Mitsubishi introduced cooling-steam in “G series” gas turbines in 1997 to cool combustor liners. Recently, some of the advanced design technologies from the M501H gas turbine were applied to the G series gas turbine resulting in significant improvement in output and thermal efficiency. A noteworthy aspect of the technology transfer is that the upgraded G series M701G2 gas turbine has an almost equivalent output and thermal efficiency as H class gas turbines while continuing to rely on conventional air cooling of turbine blades and vanes, and time-proven materials from industrial gas turbine experience. In this paper we describe the key design features of the M701G2 gas turbine that make this possible such as the advanced 21:1 compressor with 14 stages, an advanced premix DLN combustor, etc., as well as shop load test results that were completed in 2002 at Mitsubishi’s in-house facility.

Analysis of a Basic Chemically Recuperated Gas Turbine Power Plant

1994 ◽  
Vol 116 (2) ◽  
pp. 277-284 ◽  
Author(s):  
K. F. Kesser ◽  
M. A. Hoffman ◽  
J. W. Baughn
Keyword(s):  
Gas Turbine ◽  
Thermal Efficiency ◽  
Waste Heat ◽  
Computer Code ◽  
Combined Cycle ◽  
Specific Work ◽  
Turbine Cooling ◽  
Specific Heats ◽  
Methane Steam ◽  
Cooling Air

This paper investigates a “basic” Chemically Recuperated Gas Turbine (a “basic” CRGT is defined here to be one without intercooling or reheat). The CRGT is of interest due to its potential for ultralow NOx emissions. A computer code has been developed to evaluate the performance characteristics (thermal efficiency and specific work) of the Basic CRGT, and to compare it to the steam-injected gas turbine (STIG), the combined cycle (CC) and the simple cycle gas turbine (SC) using consistent assumptions. The CRGT model includes a methane-steam reformer (MSR), which converts a methane-steam mixture into a hydrogen-rich fuel using the “waste” heat in the turbine exhaust. Models for the effects of turbine cooling air, variable specific heats, and the real gas effects of steam are included. The calculated results show that the Basic CRGT has a thermal efficiency higher than the STIG and simple cycles but not quite as high as the combined cycle.

Experimental and Numerical Analysis of the Flow Structure and Dust Separation Inside a Pre-Swirl Cooling Air System

2003 ◽  
Author(s):  
O. Schneider ◽  
H. J. Dohmen ◽  
F.-K. Benra ◽  
D. Brillert
Keyword(s):  
Numerical Analysis ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Turbine Blades ◽  
Internal Cooling ◽  
Flow Conditions ◽  
Test Rig ◽  
Complex Flow ◽  
Air System ◽  
Cooling Air

Improvements in efficiency and performance of gas turbines require a better understanding of the internal cooling air system which provides the turbine blades with cooling air. With the increase of cooling air passing through the internal air system, a greater amount of air borne particles is transported to the film cooling holes at the turbine blade surface. In spite of their small size, these holes are critical for blockage. Blockage of only a few holes could have harmful effects on the cooling film surrounding the blade. As a result, a reduced mean time between maintenance or even unexpected operation faults of the gas turbine during operation could occur. Experience showed a complex interaction of cooling air under different flow conditions and its particle load. To get more familiar with all these influences and the system itself, a test rig has been built. With this test rig, the behavior of particles in the internal cooling air system can be studied at realistic flow conditions compared to a modern, heavy duty gas turbine. It is possible to simulate different particle sizes and dust concentrations in the coolant air. The test rig has been designed to give information about the quantity of separated particles at various critical areas of the internal air system [1]. The operation of the test rig as well as analysis of particles in such a complex flow system bear many problems, addressed in previous papers [1,2,3]. New theoretical studies give new and more accurate results, compared to the measurements. Furthermore the inspection of the test rig showed dust deposits at unexpected positions of the flow path, which will be discussed by numerical analysis.

scholarly journals Investigation of the Pressure Gain Characteristics and Cycle Performance in Gas Turbines Based on Interstage Bleeding Rotating Detonation Combustion

Entropy ◽  
2019 ◽  
Vol 21 (3) ◽  
pp. 265 ◽  
Author(s):  
Lei Qi ◽  
Zhitao Wang ◽  
Ningbo Zhao ◽  
Yongqiang Dai ◽  
Hongtao Zheng ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Cycle Performance ◽  
Efficiency Enhancement ◽  
Compressor Pressure Ratio ◽  
Detonation Combustion ◽  
Gas Turbine Cycle ◽  
Cycle Efficiency ◽  
Rotating Detonation

To further improve the cycle performance of gas turbines, a gas turbine cycle model based on interstage bleeding rotating detonation combustion was established using methane as fuel. Combined with a series of two-dimensional numerical simulations of a rotating detonation combustor (RDC) and calculations of cycle parameters, the pressure gain characteristics and cycle performance were investigated at different compressor pressure ratios in the study. The results showed that pressure gain characteristic of interstage bleeding RDC contributed to an obvious performance improvement in the rotating detonation gas turbine cycle compared with the conventional gas turbine cycle. The decrease of compressor pressure ratio had a positive influence on the performance improvement in the rotating detonation gas turbine cycle. With the decrease of compressor pressure ratio, the pressurization ratio of the RDC increased and finally made the power generation and cycle efficiency enhancement rates display uptrends. Under the calculated conditions, the pressurization ratios of RDC were all higher than 1.77, the decreases of turbine inlet total temperature were all more than 19 K, the power generation enhancements were all beyond 400 kW and the cycle efficiency enhancement rates were all greater than 6.72%.

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