The ultra-high efficiency gas turbine engine, UHEGT, Part II: A numerical study on reducing the stator blade surface temperature by indexing fuel injectors and using film cooling

2020 ◽  
pp. 095765092097353
Author(s):  
Seyed M Ghoreyshi ◽  
Meinhard T Schobeiri
Keyword(s):  
Surface Temperature ◽  
Gas Turbine ◽  
Film Cooling ◽  
Total Pressure ◽  
High Efficiency ◽  
Combustion Process ◽  
Blade Surface ◽  
Turbine Engine ◽  
Fuel Injectors ◽  
Stator Blade

In the Ultra-High Efficiency Gas Turbine Engine, UHEGT (introduced in our previous studies) the combustion process is no longer contained in isolation between the compressor and turbine, rather distributed within the axial gaps before each stator row. This technology substantially increases the thermal efficiency of the engine cycle to above 45%, increases power output, and reduces turbine inlet temperature. Since the combustion process is brought into the turbine stages in UHEGT, the stator blades are exposed to high-temperature gases and can be overheated. To address this issue and reduce the temperature on the stator blade surface, two different approaches are investigated in this paper. The first is indexing (clocking) of the fuel injectors (cylindrical tubes extended from hub to shroud), in which the positions of the injectors are adjusted relative to each other and the stator blades. The second is film cooling, in which cooling holes are placed on the blade surface to bring down the temperature via coolant injection. Four configurations are designed and studied via computational fluid dynamics (CFD) to evaluate the effectiveness of the two approaches. Stator blade surface temperature (as the main objective function) along with other performance parameters such as temperature non-uniformity at rotor inlet, total pressure loss over the injectors, and total power production by rotor are evaluated for all configurations. The results show that indexing presents the most promising approach in reducing the stator blade surface temperature while producing the least amount of total pressure loss.

A Numerical Study on Reducing the Stator Blade Surface Temperature in the Ultra-High Efficiency Gas Turbine Engine by Indexing Fuel Injectors and Using Film Cooling

2018 ◽  
Author(s):  
Seyed M. Ghoreyshi ◽  
Meinhard T. Schobeiri
Keyword(s):  
Surface Temperature ◽  
Gas Turbine ◽  
Film Cooling ◽  
Pressure Loss ◽  
Total Pressure ◽  
High Efficiency ◽  
Combustion Process ◽  
Blade Surface ◽  
Fuel Injectors ◽  
Stator Blade

The Ultra-High Efficiency Gas Turbine technology, UHEGT, has been introduced in our previous publications [1]-[4]. In UHEGT, the combustion process is no longer contained in isolation between the compressor and turbine, rather distributed and integrated within the axial gaps before each stator row. As shown in the previous publications, this technology substantially increases the thermal efficiency of the engine to 45% and above. Since the combustion process is brought into the turbine stages in UHEGT, the stator blades are exposed to high temperature gases and are prone to be overheated. To address this issue, two different approaches are investigated in this paper in order to control and reduce the temperature on the stator blade surface. The first approach is indexing (clocking) of the fuel injectors (cylindrical tubes extended from hub to shroud), in which the positions of the injectors are adjusted relative to each other and the stator blades. The second approach is using film cooling, in which cooling holes are added on the blade surface to bring down the temperature via coolant injection. Four configurations are designed and studied via computational fluid dynamics (CFD) to evaluate the effectiveness of the two approaches. The objective functions in this evaluation are stator blade surface temperature, temperature non-uniformity at rotor inlet, total pressure loss over the injectors, and total power production by rotor. The results show that the second configuration, which uses the indexing approach, presents the most promising case in controlling the stator blade surface temperature. This configuration produces the lowest temperature distribution over the stator blade surface and the least amount of total pressure loss.

Dynamic Behavior of the Ultra-High Efficiency Gas Turbine Engine, UHEGT, With Stator Internal Combustion

2019 ◽  
Author(s):  
Seyed M. Ghoreyshi ◽  
Meinhard T. Schobeiri
Keyword(s):  
Gas Turbine ◽  
Dynamic Behavior ◽  
Dynamic Simulation ◽  
High Efficiency ◽  
Time Lag ◽  
Combustion Process ◽  
Internal Combustion ◽  
Gas Turbine Engine ◽  
Turbine Engine ◽  
Fuel Flow

Abstract The paper investigates the dynamic behavior of an Ultra-High Efficiency Gas Turbine Engine (UHEGT) with Stator Internal Combustion. The UHEGT-technology was introduced for the first time to the gas turbine design community at the Turbo Expo 2015. In developing the UHEGT-technology, the combustion process is no longer contained in isolation between the compressor and turbine, rather distributed in the first three HP-turbine stator rows. Noticeable improvement in the engine thermal efficiency and power along with other performance advantages are brought by this technology. In the current paper, a dynamic simulation is performed on the entire gas turbine engine (UHEGT) using the nonlinear dynamic simulation code GETRAN. The simulations are in 2D (space-time) and include the majority of the engine components including rotor shaft, turbine and compressor, fuel injectors, diffuser, pipes, valves, controllers, etc. The thermo-fluid conservation laws are applied to the flow in each component which create a system of nonlinear partial differential equations that is solved numerically. Two different fuel schedules (steep rise and Gaussian) are applied to all injectors and the engine response is studied in each case. The results show that fluctuations in the fuel flow lead to fluctuations in most of the system parameters such as temperatures, power, shaft speed, etc. However, the shapes and amplitudes of the fluctuations are different and there is a time lag in the response profiles relative to the fuel schedules. It is shown that an increase in average fuel flow in the system leads to a small drop in efficiency due to the cycle change from the design point. Moreover, it is seen that the temperatures usually rise fast with increase of fuel flow, but the system tends to cool down with a slower rate as the fuel is reduced.

The ultra-high efficiency gas turbine engine, uhegt, part III: Dynamic behavior of the system in variable performance conditions

2021 ◽  
pp. 095765092110162
Author(s):  
Seyed M Ghoreyshi ◽  
Meinhard T Schobeiri
Keyword(s):  
Gas Turbine ◽  
Dynamic Behavior ◽  
Dynamic Simulation ◽  
High Efficiency ◽  
Time Lag ◽  
Combustion Process ◽  
Gas Turbine Engine ◽  
Simulation Code ◽  
Turbine Engine ◽  
Fuel Flow

This paper investigates the dynamic behavior of an Ultra-High Efficiency Gas Turbine Engine (UHEGT) with Stator Internal Combustion. The UHEGT-technology was introduced for the first time to the gas turbine design community at the Turbo Expo 2015. In developing the UHEGT-technology, the combustion process is no longer contained in isolation between the compressor and turbine, rather distributed in the first three HP-turbine stator rows. Noticeable improvement in the engine thermal efficiency and power along with other performance advantages are brought by this technology. In the current paper, dynamic simulation is performed on the entire gas turbine engine (UHEGT) using the nonlinear dynamic simulation code GETRAN. The simulations are in 2 D (space-time) and include the majority of the engine components including rotor shaft, turbine and compressor, fuel injectors, diffuser, pipes, valves, controllers, etc. The thermo-fluid conservation laws are applied to the flow in each component which create a system of nonlinear partial differential equations that is solved numerically. Two different fuel schedules (steep rise and Gaussian) are applied to all injectors and the engine response is studied in each case. The results show that fluctuations in the fuel flow lead to fluctuations in most of the system parameters such as temperatures, power, shaft speed, etc. However, the shapes and amplitudes of the fluctuations are different and there is a time lag in the response profiles relative to the fuel schedules. It is shown that an increase in average fuel flow in the system leads to a small drop in efficiency due to the cycle change from the design point. Moreover, it is seen that the temperatures usually rise fast with increase of fuel flow, but the system tends to cool down at a slower rate as the fuel is reduced.

The ultra-high efficiency gas turbine engine, UHEGT, part I: Design and numerical analysis of the multistage system

2020 ◽  
pp. 095765092095166
Author(s):  
Seyed M Ghoreyshi ◽  
Meinhard T Schobeiri
Keyword(s):  
High Pressure ◽  
Gas Turbine ◽  
Gas Turbines ◽  
High Efficiency ◽  
Combustion Process ◽  
Gas Turbine Engine ◽  
High Pressure Turbine ◽  
Turbine Engine ◽  
Gaseous Fuels ◽  
Multi Stage

The Ultra-High Efficiency Gas Turbine Engine (UHEGT) was introduced in our previous studies. In UHEGT, the combustion process is no longer contained in isolation between the compressor and turbine. It is rather distributed in multiple stages and integrated within the high-pressure turbine stator rows. Compared to the current most advanced conventional gas turbines, UHEGT considerably improves the efficiency and output power of the engine while reducing its emissions and size. In this study, a six-stage UHEGT turbine with three stages of stator internal combustion is designed and analyzed. The design represents a single spool turboshaft system for power generation using gaseous fuels. The preliminary flow path for each turbine stage is designed by the meanline approach and modified using Computational Fluid Dynamics (CFD). Unsteady CFD calculation (via commercial software ANSYS CFX) is used to simulate and optimize the flow and combustion process through high-pressure turbine stages. The results show a base thermal efficiency of above 45% is achieved. It shows a successful integration of the multi-stage combustion process into the high-pressure turbine stages and a highly uniform temperature distribution at the inlet of each rotor row. High temperatures in some areas on the stator blade surfaces are controlled using indexing of fuel injectors and stator blades.

Numerical Simulation of the Multistage Ultra-High Efficiency Gas Turbine Engine, UHEGT

2017 ◽  
Author(s):  
Seyed M. Ghoreyshi ◽  
Meinhard T. Schobeiri
Keyword(s):  
High Pressure ◽  
Temperature Distribution ◽  
Gas Turbine ◽  
Output Power ◽  
High Efficiency ◽  
Combustion Process ◽  
Flow Patterns ◽  
Flow Path ◽  
High Pressure Turbine ◽  
Turbine Engine

The Ultra-High Efficiency Gas Turbine Engine (UHEGT) was introduced in our previous studies [1]–[3]. In UHEGT, the combustion process is no longer contained in isolation between the compressor and turbine, rather distributed in multiple stages and integrated within the high-pressure turbine stator rows. Compared to the current most advanced conventional gas turbines, UHEGT considerably improves the efficiency and output power of the engine while reducing its emissions and size. In the present study, a complete six-stage turbine with three stator internal combustors is designed for UHEGT. The turbine is designed for a single spool turboshaft system used for power generation. A thermodynamic cycle that has a base thermal efficiency of above 45% is designed based on an ideal mixture of methane and air. Preliminary flow path for each turbine stage is designed by 1D/2D approach (meanline calculation). The combustors, designed based on our previous [1] and parallel studies, consist of cylindrical tubes extended from hub to shroud with thin slots on top and bottom for gaseous fuel injection. CFD calculation (via ANSYS CFX) is used to simulate the high pressure turbine stages (stage 1 to 3). The simulations are unsteady, they are performed for ten total components and include a multi-species combustion process along with the rotor motion. The flow path is modified based on the CFD results in order to reduce separation and losses while enabling maximum mixing of fuel and air and reducing temperature non-uniformities. Flow patterns, secondary flow losses, temperature distribution, and pollutant emissions are presented and analyzed in the results. The results show that a relatively uniform temperature distribution is achieved at the inlet of each rotor and the system performs very well regarding the output power and flow patterns.

Fracture of a Compressor Stator Blade in a Gas Turbine Engine

2013 ◽  
Vol 50 (1) ◽  
pp. 43-49
Author(s):  
A. Neidel ◽  
B. Matijasevic-Lux
Keyword(s):  
Gas Turbine ◽  
Gas Turbine Engine ◽  
Turbine Engine ◽  
Stator Blade

Film Cooling and Aerodynamic Performance on Multi-Cavity Squealer Tip of a Turbine Blade

2021 ◽  
Author(s):  
Feng Li ◽  
Zhao Liu ◽  
Zhenping Feng
Keyword(s):  
Gas Turbine ◽  
Film Cooling ◽  
Pressure Loss ◽  
Total Pressure ◽  
Aerodynamic Performance ◽  
Total Pressure Loss ◽  
Cooling Performance ◽  
Pressure Loss Coefficient ◽  
Blade Tip ◽  
Total Pressure Loss Coefficient

Abstract The blade tip region of the shroud-less high-pressure gas turbine is exposed to an extremely operating condition with combined high temperature and high heat transfer coefficient. It is critical to design new tip structures and apply effective cooling method to protect the blade tip. Multi-cavity squealer tip has the potential to reduce the huge thermal loads and improve the aerodynamic performance of the blade tip region. In this paper, numerical simulations were performed to predict the aerothermal performance of the multi-cavity squealer tip in a heavy-duty gas turbine cascade. Different turbulence models were validated by comparing to the experimental data. It was found that results predicted by the shear-stress transport with the γ-Reθ transition model have the best precision. Then, the film cooling performance, the flow field in the tip gap and the leakage losses were presented with several different multi-cavity squealer tip structures, under various coolant to mainstream mass flow ratios (MFR) from 0.05% to 0.15%. The results show that the ribs in the multi-cavity squealer tip could change the flow structure in the tip gap for that they would block the coolant and the leakage flow. In this study, the case with one-cavity (1C) achieves the best film cooling performance under a lower MFR. However, the cases with multi-cavity (2C, 3C, 4C) show higher film cooling effectiveness under a higher MFR of 0.15%, which are 32.6%%, 34.2%% and 41.0% higher than that of the 1C case. For the aerodynamic performance, the case with single-cavity has the largest total pressure loss coefficient in all MFR studied, whereas the case with two-cavity obtains the smallest total pressure loss coefficient, which is 7.6% lower than that of the 1C case.

Account of Film Turbulence for Predicting Film Cooling Effectiveness in Gas Turbine Combustors

1979 ◽  
Author(s):  
G. J. Sturgess
Keyword(s):  
Gas Turbine ◽  
Film Cooling ◽  
Cooling Effectiveness ◽  
Turbine Engine ◽  
Film Cooling Effectiveness ◽  
Wide Range ◽  
Engine Combustion ◽  
Turbulence Effects ◽  
The Impact ◽  
Combustor Liner

The paper deals with a small but important part of the overall gas turbine engine combustion system and continues earlier published work on turbulence effects in film cooling to cover the case of film turbulence. Film cooling of the gas turbine combustor liner imposes certain geometric limitations on the coolant injection device. The impact of practical film injection geometry on the cooling is one of increased rates of film decay when compared to the performance from idealized injection geometries at similar injection conditions. It is important to combustor durability and life estimation to be able to predict accurately the performance obtainable from a given practical slot. The coolant film is modeled as three distinct regions, and the effects of injection slot geometry on the development of each region are described in terms of film turbulence intensity and initial circumferential non-uniformity of the injected coolant. The concept of the well-designed slot is introduced and film effectiveness is shown to be dependent on it. Only slots which can be described as well-designed are of interest in practical equipment design. A prediction procedure is provided for well-designed slots which describes growth of the film downstream of the first of the three film regions. Comparisons of predictions with measured data are made for several very different well-designed slots over a relatively wide range of injection conditions, and good agreement is shown.

Effect of Divergence Angle on Flow Through Inlet Section of Diffuser of a Gas Turbine Combustion Chamber: The CFD Approach

2006 ◽  
Author(s):  
Digvijay B. Kulshreshtha ◽  
S. A. Channiwala ◽  
Jitendra Chaudhary ◽  
Zoeb Lakdawala ◽  
Hitesh Solanki ◽  
...  
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
Total Pressure ◽  
Divergence Angle ◽  
Velocity Head ◽  
Turbine Engine ◽  
Inlet Velocity ◽  
Pressure Losses ◽  
Flow Through ◽  
Mach Numbers

In the combustor inlet diffuser section of gas turbine engine, high-velocity air from compressor flows into the diffuser, where a considerable portion of the inlet velocity head PT3 − PS3 is converted to static pressure (PS) before the airflow enters the combustor. Modern high through-flow turbine engine compressors are highly loaded and usually have high inlet Mach numbers. With high compressor exit Mach numbers, the velocity head at the compressor exit station may be as high as 10% of the total pressure. The function of the diffuser is to recover a large proportion of this energy. Otherwise, the resulting higher total pressure loss would result in a significantly higher level of engine specific fuel consumption. The diffuser performance must also be sensitive to inlet velocity profiles and geometrical variations of the combustor relative to the location of the pre-diffuser exit flow path. Low diffuser pressure losses with high Mach numbers are more rapidly achieved with increasing length. However, diffuser length must be short to minimize engine length and weight. A good diffuser design should have a well considered balance between the confliction requirements for low pressure losses and short engine lengths. The present paper describes the effect of divergence angle on diffuser performance for gas turbine combustion chamber using Computational Fluid Dynamic Approach. The flow through the diffuser is numerically solved for divergence angles ranging from 5 to 25°. The flow separation and formation of wake regions are studied.

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