Flow development and turbulence length scales within an annular gas turbine exhaust diffuser

Ubertini, Stefano; Desideri, Umberto

doi:10.1016/s0894-1777(00)00011-x

Cited by 10 publications

(4 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The values of the relative and absolute error thresholds for q have been taken equal to D q =0.25 and W q =0.03 for velocity and to D q =0.25 and W q =0.003 for k. The threshold for absolute error is based on the uncertainty of the experiment. Here, the uncertainty on velocity measurements was not explicitly mentioned in the experimental report but it was estimated based on the anemometer manufacturer information (Jørgensen, 2002) and experiments performed with the same equipment (Ubertini and Desideri, 2000).…”

Section: List Of Casesmentioning

confidence: 99%

Quality assessment of Large-Eddy Simulation of wind flow around a high-rise building: Validation and solution verification

2013

View full text Add to dashboard Cite

When undertaking wind engineering problems such as urban pollutant dispersion or pedestrian wind comfort with Computational Fluid Dynamics, an accurate simulation of the flow-field around buildings is required. In this respect, the good performance of Large-Eddy Simulation has already been established but because the formulation and the use of this turbulence modeling approach are complex, the uncertainty on the results is relatively high. This implies the need for validation and verification (V&V) studies like the one performed in the present paper for the wind flow around an isolated high-rise building with aspect ratio 1:1:2. In the first part of the study, the numerical results are compared with measurements from a reference wind-tunnel experiment and the agreement is quantified by validation metrics. The vortex method to generate inflow turbulence is shown to provide accurate results. Unexpectedly, the best agreement with the experiments is obtained on the coarsest computational grid, with 20 cells per building side, while a finer grid with 30 cells per building side overestimates the turbulent kinetic energy measurements. A similar result was also found by earlier studies for different flow configurations. In the second part of the study, solution verification is performed. The Systematic Grid and Model Variation technique is used to provide estimates of the modeling and numerical error contributions. The LES_IQ indicator shows that a grid with 20 (resp. 30) cells per building side allows resolving 80% (resp. 91%) of the total turbulent kinetic energy in the region around the building.

show abstract

Section: List Of Casesmentioning

confidence: 99%

Quality assessment of Large-Eddy Simulation of wind flow around a high-rise building: Validation and solution verification

2013

View full text Add to dashboard Cite

show abstract

“…Their comparison with the available experimental data exhibits the reproduction of the essential fluid flow and heat transfer features. Ubertini and Desideri [20,21] have reported experimental work on an annular gas turbine exhaust diffuser. In the former article [20], they focused on the distortion of the flow produced by the struts and on the separation around the hub and the shell.…”

Section: Introductionmentioning

confidence: 99%

“…They also investigated the diffuser flow in terms of the turbulent scale of dissipating eddies, as in the Kolmogorov theory [22]. In the second article [21], they highlighted the effect of struts on the total and static pressure development and on the local phenomena and the overall performance. Barker and Carrotte [23,24] studied the influence of compressor exit conditions on the combustor annular diffuser performance and flow redistribution.…”

Section: Introductionmentioning

confidence: 99%

Effect of inlet swirl on the performance of annular diffusers having the same equivalent cone angle

Singh

Seshadri

Saha

et al. 2006

Proceedings of the Institution of Mechanical Engineers, Part G:

View full text Add to dashboard Cite

Annular diffusers are an integral component of the gas turbine engines of high-speed aircraft. These facilitate effective operation of the combustor by reducing the total pressure loss. The performance characteristics of these diffusers depend on their geometry and the inlet conditions. The present investigation attempts to select the range of the inlet swirl intensity for the best performance of annular diffusers with different geometries but having the same equivalent cone angle. This is analysed on the basis of the static pressure recovery and total pressure loss coefficients. The results show that the parallel diverging hub and casing annular diffuser produces the best performance at high-swirl intensities.

show abstract

“…The availability of numerical method for the aerodynamic performance predictions of the exhaust diffuser was validated. Ubertini and Desideri 6 conducted an experimental investigation of the velocity field in the model of the PGT10 gas turbine exhaust diffuser and analyzed its flow physics and turbulence length scale. Zarifi-Rad et al 7 numerically presented the velocity and static pressure profiles along with the exhaust diffuser of gas turbines based on experimental data of the 1:12 scale model.…”

Section: Introductionmentioning

confidence: 99%

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

Dong

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part A:

View full text Add to dashboard Cite

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.

show abstract

Flow development and turbulence length scales within an annular gas turbine exhaust diffuser

Cited by 10 publications

References 23 publications

Quality assessment of Large-Eddy Simulation of wind flow around a high-rise building: Validation and solution verification

Quality assessment of Large-Eddy Simulation of wind flow around a high-rise building: Validation and solution verification

Effect of inlet swirl on the performance of annular diffusers having the same equivalent cone angle

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

Contact Info

Product

Resources

About