Studies on Stepped Air Ejector Diffusers incorporating Heat Transfer Effects

2018 ◽  
Vol 35 (3) ◽  
pp. 251-263 ◽  
Author(s):  
Parminder Singh ◽  
SidhNath Singh ◽  
V Seshadri
Keyword(s):  
Static Pressure ◽  
Numerical Study ◽  
Ambient Air ◽  
Exhaust Gases ◽  
Cold Flow ◽  
Annular Slot ◽  
Passive Devices ◽  
Gas Turbine Exhaust ◽  
Air Ejector ◽  
Turbine Exhaust

Abstract Air ejector diffusers are employed in gas turbine exhaust systems to cool the exhaust gases. These diffusers are developed as passive devices, which use the energy of the main flow to entrain the relatively cool ambient air through the annular slot openings. Multiple slot openings are provided along the length of ejector diffusers to lower the temperatures of the exhaust gases. This paper presents results of a 3-D numerical study carried out at a fixed Reynolds Number of 2.5×105 with a corresponding inlet Mach number of about 0.22 on three configurations of a non-circular ejector diffuser having an overall area ratio of 9. The three configurations being investigated are the best diffuser configurations established on the basis of cold flow studies reported in literature. The results are presented in terms of temperature distribution, entrainment mass flux rates and static pressure recovery. The results show that the higher number of slot openings improves cooling in the ejector diffuser as compared to thicker interfaces or inclination at the slot inlet.

An Experimental Analysis of Flow Through Annular Diffuser With and Without Struts

2006 ◽  
Author(s):  
R. Prakash ◽  
P. Sudhakar ◽  
N. V. Mahalakshmi
Keyword(s):  
Gas Turbine ◽  
Static Pressure ◽  
Structural Members ◽  
Pressure Development ◽  
Annular Diffuser ◽  
Fundamental Research ◽  
Flow Through ◽  
Gas Turbine Exhaust ◽  
Industrial Gas Turbine ◽  
Turbine Exhaust

This paper presents the static pressure development and the effect of struts on the performance of an annular diffuser. A typical exhaust diffuser of an industrial gas turbine is annular with structural members, called struts, which extend radially from the inner to the outer annulus wall. An annular diffuser model, primarily intended for fundamental research, has been tested on a wind tunnel. Similar conditions that prevail in an industrial gas turbine have been generated in the diffuser. Measurements were made using a five holed Pitot probe. The research had been carried out to make a detailed investigation on the effect of struts and to advance computational and design tools for gas turbine exhaust diffusers.

OPTIMIZING CERAMIC KILN OPERATION UTILIZING INDUSTRIAL GAS TURBINE EXHAUST GASES

Clean Air ◽  
2004 ◽  
Vol 5 (3) ◽  
pp. 243-266
Author(s):  
L. M. Fletcher ◽  
D. K. Iatridis ◽  
A. N. Katsanevakis ◽  
A. A. Lappas ◽  
O. Monachos ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Exhaust Gases ◽  
Gas Turbine Exhaust ◽  
Industrial Gas Turbine ◽  
Turbine Exhaust

An experimental investigation into the use of molten carbonate fuel cells to capture CO2 from gas turbine exhaust gases

Energy ◽  
2004 ◽  
Vol 29 (9-10) ◽  
pp. 1279-1284 ◽  
Author(s):  
A Amorelli ◽  
M.B Wilkinson ◽  
P Bedont ◽  
P Capobianco ◽  
B Marcenaro ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Fuel Cells ◽  
Gas Turbine ◽  
Molten Carbonate ◽  
Exhaust Gases ◽  
Molten Carbonate Fuel Cells ◽  
Gas Turbine Exhaust ◽  
Turbine Exhaust

Effects of struts profiles and skewed angles on the aerodynamic performance of gas turbine exhaust diffuser

2021 ◽  
pp. 095765092098520
Author(s):  
Yuxuan Dong ◽  
Zhigang Li ◽  
Jun Li ◽  
Liming Song
Keyword(s):  
Gas Turbine ◽  
Static Pressure ◽  
Three Dimensional ◽  
Aerodynamic Performance ◽  
Pressure Recovery ◽  
Recovery Coefficient ◽  
Flow Field Characteristics ◽  
Gas Turbine Exhaust ◽  
Pressure Recovery Coefficient ◽  
Turbine Exhaust

The strut structure directly affects the flow field characteristics and aerodynamic performance of the gas turbine exhaust diffuser. The effects of the strut profiles and strut skewed angles on the aerodynamic performance of the exhaust diffuser at different inlet pre-swirls were numerically investigated using three-dimensional Reynolds-Averaged Navier-Stokes(RANS) and Realizable k-ε turbulence model. The numerical static pressure recovery coefficient of the exhaust diffuser is in agreement with the experimental data well. The reliability of the numerical method for the exhaust diffuser performance analysis was demonstrated. Exhaust diffusers with four kinds of vertical strut profiles obtain the highest static pressure recovery coefficient at the inlet pre-swirl of 0.35. The similar static pressure recovery coefficient of exhaust diffusers with four kinds of vertical strut airfoils are observed when the inlet pre-swirl is less than 0.48. The static pressure recovery coefficient of exhaust diffusers with vertical b1 and b2 struts are higher than that with the a1 and a2 struts when the inlet pre-swirl is greater than 0.48. At the inlet pre-swirl of 0.35, The static pressure recovery coefficient of the exhaust diffuser with the a1 strut decreases with the increasing of the strut skewed angles. The static pressure recovery coefficient of the exhaust diffuser with the b1 strut increases with the increasing of the strut skewed angles, and the static pressure recovery coefficient increases by 3.6% compared with the vertical design when the skewed angle of b1 strut is 40[Formula: see text]. At the inlet pre-swirl of 0.64. The static pressure recovery coefficient of the exhaust diffuser with the a1 strut increases by 8.7% compared with the vertical design when the skewed angle of a1 strut is greater than 20°. In addition, the static pressure recovery coefficient of the exhaust diffuser with the b1 strut decreases by 3.8% compared with the vertical design when the skewed angle of b1 strut is 40°. The method to improve the aerodynamic performance of the exhaust diffuser by appropriate increase the strut maximum thickness and design the strut skewed angle is proposed in this work.

Importance of Inlet Total Pressure Conditions in Evaluating Performance of Non-Symmetric Gas Turbine Exhaust Ducts

2002 ◽  
Author(s):  
M. H. Cunningham ◽  
A. M. Birk ◽  
W. Di Bartolomeo
Keyword(s):  
Gas Turbine ◽  
Total Pressure ◽  
Computational Study ◽  
Experimental Studies ◽  
Geometric Optimization ◽  
Cold Flow ◽  
Exhaust Duct ◽  
Inlet Conditions ◽  
Gas Turbine Exhaust ◽  
Turbine Exhaust

When highly non-symmetric exhaust ducts are installed on a gas turbine engine, the asymmetries result in a non-uniform circumferential total pressure condition at the inlet of the duct. When testing these ducts experimentally or computationally the correct inlet conditions are often not known or cannot be reproduced. To study the sensitivity of duct performance to inlet conditions, an experimental and computational study of a non-symmetric gas turbine exhaust duct that includes a 160° turn with an annular to rectangular transition, has been carried out over a range of inlet conditions. The inlet conditions varied include circumferential total pressure profiles and swirl. The experimental studies have been carried out in cold flow with several non-uniform total pressure inlet conditions. Computational fluid dynamic (CFD) techniques validated against the experimental results, have been used to extend the range of inlet conditions beyond the range that could be obtained experimentally to those typical of an engine installation. Results show that the total pressure inlet conditions have a significant effect on the flow structure in the exhaust duct and that the performance of the exhaust duct degrades as the level of circumferential non-uniformities increase. However, trends in geometric optimization identified experimentally using cold flow and uniform total pressure inlet conditions are confirmed computationally with circumferential non-uniformities typical of actual engine operations. This suggests that although inlet conditions are important for determining the level of performance, the configuration of the optimized geometry is somewhat independent of the inlet conditions.

Numerical investigations on the effect of volute casing treatment for performance augmentation in a centrifugal fan

2021 ◽  
pp. 095440622110341
Author(s):  
Manjunath L Nilugal ◽  
K Vasudeva Karanth ◽  
Madhwesh N
Keyword(s):  
Total Pressure ◽  
Static Pressure ◽  
Numerical Study ◽  
Pressure Coefficient ◽  
Three Dimensional ◽  
Pressure Rise ◽  
Centrifugal Fan ◽  
Casing Treatment ◽  
Sliding Mesh ◽  
Optimum Configuration

This article presents the effect of volute chamfering on the performance of a forward swept centrifugal fan. The numerical analysis is performed to obtain the performance parameters such as static pressure rise coefficient and total pressure coefficient for various flow coefficients. The chamfer ratio for the volute is optimized parametrically by providing a chamfer on either side of the volute. The influence of the chamfer ratio on the three dimensional flow domain was investigated numerically. The simulation is carried out using Re-Normalisation Group (RNG) k-[Formula: see text] turbulence model. The transient simulation of the fan system is done using standard sliding mesh method available in Fluent. It is found from the analysis that, configuration with chamfer ratio of 4.4 is found be the optimum configuration in terms of better performance characteristics. On an average, this optimum configuration provides improvement of about 6.3% in static pressure rise coefficient when compared to the base model. This optimized chamfer configuration also gives a higher total pressure coefficient of about 3% validating the augmentation in static pressure rise coefficient with respect to the base model. Hence, this numerical study establishes the effectiveness of optimally providing volute chamfer on the overall performance improvement of forward bladed centrifugal fan.

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