Numerical Investigation of an Air-Air Ejector with Diffuser for use in Gas Turbine Exhaust Systems

Author(s):  
David Cerantola ◽  
James Crawford ◽  
A. Birk
Author(s):  
Asim Maqsood ◽  
A. M. Birk

Ejectors are commonly employed in gas turbine exhaust systems for reasons such as space ventilation and IR suppression. Ejectors may incorporate bends in the geometry for various reasons. Studies have shown that the bend has a deteriorating effect on the performance of an ejector. This work was aimed to investigate the effect of exhaust gas swirl on improving the performance of a bent ejector. Four short oblong ejectors with different degrees of bend in the mixing tube and four swirl conditions were tested in this study. The primary nozzle, in all cases, was composed of a circular to oblong transition. Testing was performed at ambient and hot primary flow with 0deg, 10deg, 20deg, and 30deg swirl angles. It was observed that the swirl had a strong affect on the performance of a bent ejector. Improvement of up to 55%, 96%, and 180% was obtained in the pumping ratio, pressure rise, and total efficiency, respectively, with a 20deg swirl in the exhaust gas.


Author(s):  
Asim Maqsood ◽  
A. M. Birk

Ejectors are commonly employed in gas turbine exhaust systems for reasons such as space ventilation and IR suppression. Ejectors may incorporate bends in the geometry for various reasons. Studies have shown that the bend has a deteriorating effect on the performance of an ejector. This work was aimed to investigate the effect of exhaust gas swirl on improving the performance of a bent ejector. Four short oblong ejectors with different degrees of bend in the mixing tube and four swirl conditions were tested in this study. The primary nozzle, in all the cases, was composed of a circular to oblong transition. Testing was performed at ambient and hot primary flow with 0, 10, 20 and 30° swirl angles. It was observed that the swirl had a strong affect on the performance of a bent ejector. Improvement of up to 55, 96 and 180% was obtained in the pumping ratio, pressure rise and total efficiency respectively with a 20° swirl in the exhaust gas.


1974 ◽  
Vol 96 (3) ◽  
pp. 181-184 ◽  
Author(s):  
J. R. Cummins

To investigate the sources of acoustic radiation from a gas turbine exhaust, a one-seventh scale model has been constructed. The model geometrically scales the flow path downstream of the rotating parts including support struts and turning vanes. A discussion and comparison of different kinds of aerodynamic and acoustic scaling techniques are given. The effect of the temperature ratio between model and prototype is found to be an important parameter in comparing acoustical data.


Author(s):  
Orlando Ugarte ◽  
Suresh Menon ◽  
Wayne Rattigan ◽  
Paul Winstanley ◽  
Priyank Saxena ◽  
...  

Abstract In recent years, there is a growing interest in blending hydrogen with natural gas fuels to produce low carbon electricity. It is important to evaluate the safety of gas turbine packages under these conditions, such as late-light off and flameout scenarios. However, the assessment of the safety risks by performing experiments in full-scale exhaust ducts is a very expensive and, potentially, risky endeavor. Computational simulations using a high fidelity CFD model provide a cost-effective way of assessing the safety risk. In this study, a computational model is implemented to perform three dimensional, compressible and unsteady simulations of reacting flows in a gas turbine exhaust duct. Computational results were validated against data obtained at the simulated conditions in a representative geometry. Due to the enormous size of the geometry, special attention was given to the discretization of the computational domain and the combustion model. Results show that CFD model predicts main features of the pressure rise driven by the combustion process. The peak pressures obtained computationally and experimentally differed in 20%. This difference increased up to 45% by reducing the preheated inflow conditions. The effects of rig geometry and flow conditions on the accuracy of the CFD model are discussed.


Author(s):  
W. V. Hambleton

This paper represents a study of the overall problems encountered in large gas turbine exhaust heat recovery systems. A number of specific installations are described, including systems recovering heat in other than the conventional form of steam generation.


1968 ◽  
Vol 90 (3) ◽  
pp. 265-270 ◽  
Author(s):  
C. G. Ringwall ◽  
L. R. Kelley

Circuit concepts and test data for a fluidic system to sense the average temperature in a gas turbine exhaust duct are presented. Phase discrimination techniques are used to sense the average wave velocity in a long tube and to produce an output pressure differential proportional to temperature error.


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