Implementation of Wide Diffusion Angle V-Shaped Holes for Gas Turbine Cooling: Design Phase and Numerical Simulation

2020 ◽  
Author(s):  
V. Odemondo ◽  
L. Abba ◽  
R. Abram
Keyword(s):  
Geometrical Parameters ◽  
Outlet Section ◽  
Inlet Section ◽  
Cfd Analysis ◽  
Turbine Cooling ◽  
Expansion Angle ◽  
Cooling Design ◽  
Cylindrical Holes ◽  
Gas Turbine Cooling ◽  
Hole Geometry

Abstract This paper describes the design process carried out to develop a new hole geometry. This geometry is able to increase the cooling coverage effect on a turbine blade, in order to have a higher efficiency compared to the standard holes. The first step of the activity described is a CFD analysis of the performances of different hole geometries on a flat plate. Starting from the cylindrical holes the performances of several geometries have been compared. This study allowed the determination of the geometrical parameters mostly responsible of the film effectiveness increase. In this way a criterion able to optimize the hole geometry has been found. Keeping as constraint the same inlet section for all the geometries, the shape of the outlet section was modified in order to maximize the film coverage performances. An optimized hole geometry had been determined. This solution, called V-Shaped hole is characterized by a wide lateral expansion angle and a negligible laidback angle and it is able to increase the cooling effectiveness compared to cylindrical and shaped holes with typical expansion angles (lateral and laidback about 10°). Finally, a comparison with an experimental campaign has been performed to confirm the main results of the CFD analysis.

scholarly journals CFD Analysis of Heat Pipe Heat Exchanger to Predict the Temperature Distribution.

2020 ◽  
Vol 9 (4) ◽  
pp. 2670-2675
Keyword(s):  
Heat Exchanger ◽  
Temperature Distribution ◽  
Kinetic Energy ◽  
Heat Pipe ◽  
Fluid Dynamic ◽  
Turbulence Kinetic Energy ◽  
Outlet Section ◽  
Inlet Section ◽  
Cfd Analysis ◽  
Pipe Heat

The Computational Fluid Dynamic (CFD) Analysis of Heat Pipe Heat Exchanger (HPHE) is done to predict the temperature distribution using ANSYS-ICEM modular/meshing and FLUENT solver. In this study, HPHE is modeled in four different cases with and without fillet near the inlet and outlet sections including (standard HPHE, with enlarge inlet and outlet sections, with horizontal plate near the entrance zone, using three different cone of angles (36.03 degree, 30 degree and 45 degree)). The mass flow rate 3.75kg/sec of hot air or gas as given at the inlet section. The Standard k- -Realizable turbulence model was used for fluid flow in simulations. The magnitude and location of the temperature distribution, velocity, and turbulence kinetic energy are influenced by prescribed conditions. However, pressure drop is reduced up-to certain extent (due to change in turbulence kinetic energy) for all the cases in which round corner/fillet at the inlet and outlet section was made in the model. At the same time jet type flow is also reduced because of reduction in axial velocity and increment of Y & Z directional velocity which tends to expansion of flow toward the y and z direction.

scholarly journals Effect of Flow Rate on Turbulence Dissipation Rate Distribution in a Multiphase Pump

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 886
Author(s):  
Zongliu Huang ◽  
Guangtai Shi ◽  
Xiaobing Liu ◽  
Haigang Wen
Keyword(s):  
Flow Rate ◽  
Dissipation Rate ◽  
Circumferential Direction ◽  
Outlet Section ◽  
Inlet Section ◽  
Distribution Characteristics ◽  
Rate Condition ◽  
Rate Distribution ◽  
Multiphase Pump ◽  
Rotating Impeller

The turbulence dissipation will cause the increment of energy loss in the multiphase pump and deteriorate the pump performance. In order to research the turbulence dissipation rate distribution characteristics in the pressurized unit of the multiphase pump, the spiral axial flow type multiphase pump is researched numerically in the present study. This research is focused on the turbulence dissipation rate distribution characteristics in the directions of inlet to outlet, hub to rim, and in the circumferential direction of the rotating impeller blades. Numerical simulation based on the RANS (Reynolds averaged Navier–Stokes equations) and the k-ω SST (Shear Stress Transport) turbulence model has been carried out. The numerical method is verified by comparing the numerical results with the experimental data. Results show that the regions of the large turbulence dissipation rate are mainly at the inlet and outlet of the rotating impeller and static impeller, while it is almost zero from the inlet to the middle of outlet in the suction surface and pressure surface of the first-stage rotating impeller blades. The turbulence dissipation rate is increased gradually from the hub to the rim of the inlet section of the first-stage rotating impeller, while it is decreased firstly and then increased on the middle and outlet sections. The turbulence dissipation rate distributes unevenly in the circumferential direction on the outlet section. The maximum value of the turbulence dissipation rate occurs at 0.9 times of the rated flow rate, while the minimum value at 1.5 times of the rated flow rate. Four turning points in the turbulence dissipation rate distribution that are the same as the number of impeller blades occur at 0.5 times the blade height at 0.9 times the rated flow rate condition. The turbulence dissipation rate distribution characteristics in the pressurized unit of the multiphase pump have been studied carefully in this paper, and the research results have an important significance for improving the performance of the multiphase pump theoretically.

scholarly journals Two-Stage Evaporative Inlet Air Gas Turbine Cooling

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1382
Author(s):  
Obida Zeitoun
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Evaporative Cooling ◽  
Air Cooling ◽  
Vapor Compression ◽  
Two Stage ◽  
Turbine Cooling ◽  
Riyadh City ◽  
Vapor Compression Refrigeration ◽  
Gas Turbine Cooling

Gas turbine inlet air-cooling (TIAC) is an established technology for augmenting gas turbine output and efficiency, especially in hot regions. TIAC using evaporative cooling is suitable for hot, dry regions; however, the cooling is limited by the ambient wet-bulb temperature. This study investigates two-stage evaporative TIAC under the harsh weather of Riyadh city. The two-stage evaporative TIAC system consists of indirect and direct evaporative stages. In the indirect stage, air is precooled using water cooled in a cooling tower. In the direct stage, adiabatic saturation cools the air. This investigation was conducted for the GE 7001EA gas turbine model. Thermoflex software was used to simulate the GE 7001EA gas turbine using different TIAC systems including evaporative, two-stage evaporative, hybrid absorption refrigeration evaporative and hybrid vapor-compression refrigeration evaporative cooling systems. Comparisons of different performance parameters of gas turbines were conducted. The added annual profit and payback period were estimated for different TIAC systems.

Geometrical parameters effect of recessed nozzle inlet section on the flow coefficient

2020 ◽  
Vol 27 (2) ◽  
pp. 140-148
Author(s):  
Andrey Sabirzyanov ◽  
Anna Kirillova ◽  
Chulpan Khamatnurova
Keyword(s):  
Flow Coefficient ◽  
Geometrical Parameters ◽  
Inlet Section ◽  
Nozzle Inlet

Build Direction Effects on Additively Manufactured Channels

2015 ◽  
Author(s):  
Jacob C. Snyder ◽  
Curtis K. Stimpson ◽  
Karen A. Thole ◽  
Dominic Mongillo
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Pressure Loss ◽  
Small Scale ◽  
Turbine Cooling ◽  
Gas Turbine Cooling ◽  
Gas Turbine Heat Transfer ◽  
Manufacturing Techniques ◽  
Traditional Manufacturing

With the advances of Direct Metal Laser Sintering (DMLS), also generically referred to as additive manufacturing, novel geometric features of internal channels for gas turbine cooling can be achieved beyond those features using traditional manufacturing techniques. There are many variables, however, in the DMLS process that affect the final quality of the part. Of most interest to gas turbine heat transfer designers are the roughness levels and tolerance levels that can be held for the internal channels. This study investigates the effect of DMLS build direction and channel shape on the pressure loss and heat transfer measurements of small scale channels. Results indicate that differences in pressure loss occur between the test cases with differing channel shapes and build directions, while little change is measured in heat transfer performance.

CFD-Analysis of Coverplate Receiver Flow

1996 ◽  
Author(s):  
Oliver Popp ◽  
Horst Zimmermann ◽  
J. Kutz
Keyword(s):  
Turbine Rotor ◽  
Geometrical Parameters ◽  
Receiver Design ◽  
Cfd Analysis ◽  
Efficiency Improvement ◽  
System Efficiency ◽  
Cfd Simulations ◽  
Air Supply ◽  
Cooling Air ◽  
Contour Design

The flow field in a preswirled cooling air supply to a turbine rotor has been investigated by means of CFD-simulations. Coefficients for system efficiency are derived. The influences of various geometrical parameters for different configurations have been correlated with the help of appropriate coefficients. For some of the most important geometrical parameters of the coverplate receiver design recommendations have been found. For the preswirl nozzles the potential of efficiency improvement by contour design is highlighted.

Scaling Heat-Transfer Coefficients Measured Under Laboratory Conditions to Engine Conditions

2017 ◽  
Author(s):  
T. I.-P. Shih ◽  
C.-S. Lee ◽  
K. M. Bryden
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Gas Turbine ◽  
Scaling Factor ◽  
Rate Of Change ◽  
Transfer Enhancement ◽  
Scaling Factors ◽  
Turbine Cooling ◽  
Pin Fins ◽  
Gas Turbine Cooling

Almost all measurements of the heat-transfer coefficient (HTC) or Nusselt number (Nu) in gas-turbine cooling passages with heat-transfer enhancement features such as pin fins and ribs have been made under conditions, where the wall-to-bulk temperature, Tw/Tb, is near unity. Since Tw/Tb in gas-turbine cooling passages can be as high as 2.2 and vary appreciably along the passage, this study examines if it is necessary to match the rate of change in Tw/Tb when measuring Nu, whether Nu measured at Tw/Tb near unity needs to be scaled before used in design and analysis of turbine cooling, and could that scaling for ducts with heat-transfer enhancement features be obtained from scaling factors for smooth ducts because those scaling factors exist in the literature. In this study, a review of the data in the literature shows that it is unnecessary to match the rate of change in Tw/Tb for smooth ducts at least for the rates that occur in gas turbines. For ducts with heat-transfer enhancement features, it is still an open question. This study also shows Nu measured at Tw/Tb near unity needs to be scale to the correct Tw/Tb before it can be used for engine conditions. By using steady RANS analysis of the flow and heat transfer in a cooling channel with a staggered array of pin fins, the usefulness of the scaling factor, (Tw/Tb)r, from the literature for smooth ducts was examined. Nuengine, computed under engine conditions, was compared with those computed under laboratory conditions, Nulab, and scaled by (Tw/Tb)r; i.e., Nulab,scaled = Nulab (Tw/Tb)r. Results obtained show the error in Nulab,scaled relative to Nuengine can be as high as 36.6% if r = −0.7 and Tw/Tb = 1.573 in the “fully” developed region. Thus, (Tw/Tb)r based on smooth duct should not be used as a scaling factor for Nu in cooling passages with heat-transfer enhancement features. To address this inadequacy, a method is proposed for generating scaling factors, and a scaling factor was developed to scale the heat transfer from laboratory to engine conditions for a channel with pin fins.

scholarly journals The 701F Gas Turbine Design Process: Upgrade and Innovations

1999 ◽  
Author(s):  
B. Facchini ◽  
C. Carcasci ◽  
G. Ferrara ◽  
L. Innocenti ◽  
D. Coutandin ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Design Process ◽  
Cooling System ◽  
Design Procedure ◽  
Operating Conditions ◽  
Pollutant Emission ◽  
Inlet Section ◽  
Blade Cooling ◽  
Cooling Design ◽  
Power Capability

In this paper, a Fiat Avio 701F gas turbine re-design process is presented. This already tested gas turbine has been modified, for a particular re-powering application: a reduction in the net power production is required, whereas efficiency and exhaust temperature have been improved by mean of increased hot gas temperature at the first nozzle inlet section. Consequently this re-powering solution clearly requires consistent re-design efforts to satisfy specific plant operating conditions. The gas turbine power output has been tuned to the required value by reducing the air inlet mass flowrate; the combustion chamber setting has been modified with particular attention to the control of pollutant emission level. The increase of inlet stator turbine temperature necessitated a complete review of the three cooled turbine stages. The aim of greater overall efficiency with inlet and exit turbine temperature increase also involved the introduction of a new blade material. For design tool flexibility the blade cooling design procedure has been improved making better optimization of the cooling system possible. In this paper a detailed description of the several gas turbine modifications with particular attention to the blade cooling design procedure and to the corresponding simulation results is reported. The modifications developed could also be introduced on the new version of the 701F, at full power capability, in order to get better efficiency and power.

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