Thermodynamic Analyses of Wet Compression Process in the Compressor of Gas Turbine

Zheng, Qun; Sun, Yufeng; Li, Shuying; Wang, Yunhui

doi:10.1115/gt2002-30590

Cited by 40 publications

(30 citation statements)

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“…where k is the turbulent kinetic energy, ε is the turbulent kinetic energy dissipation rate and c μ is a model constant. Then, one could possibly evaluate the local Stokes number according to: According to Zheng et al [29], particles smaller than 5 m μ in diameter can follow the flow closely in gas turbines. This is because in their opinion, small particles have small response time, thus achieving velocity equilibrium with the continuous phase in a small amount of time.…”

Section: Stokes Numbermentioning

confidence: 99%

“…Since particles smaller than 5-20 m μ in diameter can follow the flow very closely [2], [29], dispersion of particles due to turbulence can be considered negligible. It was also thought that if a small initial particle diameter were chosen then the momentum exchange between phases would be low.…”

Section: Effect Of Water Injection On Rotor Performance Under Design mentioning

confidence: 99%

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A Numerical Study of Water Injection on Transonic Compressor Rotor Performance

Szabó

2007

45th AIAA Aerospace Sciences Meeting and Exhibit

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In this study, numerical simulations of two-phase flow in a transonic compressor rotor (NASA rotor 37) were performed. Both flow and droplets' governing equations were formulated and solved in the reference frame of the rotating blades. An Eulerian-Lagrangian approach was used for the continuous and discrete phases with a two-way interaction model to simulate the mass-, momentum-and energy exchange between the different phases. Water particles were injected at the inlet with uniform particle mass flux, fully evaporating inside the rotating blade row. The phase change was most intense in areas adjacent to shock waves, where the slip velocity of the droplets was the highest. Results show decreased circumferentially averaged total temperature ratio of the air-vapor mixture across the span, which is the direct result of inter-phase energy coupling. An entropy based approach to calculate the isentropic efficiency of a wet compression process in a transonic compressor rotor was also presented. Under the proposed method, the viscous dissipation function was calculated everywhere in the domain in the post-processing phase of the numerical simulation and integrated to the wall, with special treatment in the nearwall regions where high rates of entropy generation occur. For a water to air mass flow ratio of 1% results show increased entropy production across the span, resulting in a 5% drop in compressor isentropic efficiency. Analytical integration of wall functions and numerical integration of the viscous dissipation function allows for reasonable results even with relatively coarse grids and can also be applied for single-phase flows. A parametric study of the effect of initial particle parameters on the wet compression process was also performed. Several speedlines have been computed with different amounts of water, especially near the tip. Results show that numerical stall can be delayed with injection of water near the tip, due to the increase of the axial momentum of the fluid in the endwall region, which is the direct result of phase change.iv v ACKNOWLEDGEMENT

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Section: Stokes Numbermentioning

confidence: 99%

Section: Effect Of Water Injection On Rotor Performance Under Design mentioning

confidence: 99%

A Numerical Study of Water Injection on Transonic Compressor Rotor Performance

Szabó

2007

45th AIAA Aerospace Sciences Meeting and Exhibit

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“…Thermodynamic and analytical studies on wet compression have indicated that it can improve the compressor performance and the overall gas turbine performance [1][2][3][4][5][6]. Thermodynamic models of ideal and actual wet compression processes, developed by Zheng et al [1], clearly showed performance gains achievable with the wet compression. White and Meacock [2] discussed the high fogging effects on the work of compression and the effects on the stage-by-stage compressor performance.…”

Section: Introductionmentioning

confidence: 99%

The Effects of Wet Compression and Blade Tip Water Injection on the Stability of a Transonic Compressor Rotor

Luo¹,

Zheng²,

Sun³

et al. 2012

Journal of Engineering for Gas Turbines and Power

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The rotor blade tip leakage fiow and associated formation of the tip leakage vortex and interaction of the tip leakage vortex with the shockwave, particularly in the case of a transonic compressor rotor have significant impact on the compressor performance and its stability. Air injection upstream of the compressor rotor tip has been shown to improve compressor performance and enhance its stability. The air required for rotor blade tip injection is generally taken from the later stages of the compressor thus causing penalty on the gas turbine performance. In this study, effects of water injection at the rotor tip with and without the wet compression on the compressor performance and its stability have been examined. To achieve the stated objectives, the well tested transonic compressor rotor stage, NASA rotor stage 37, has been numerically simulated. The evaluation of results on various performance parameters, such as total pressure ratio, inlet fiow capacity, and adiabatic efficiency combined with contours of total pressure losses, entropy. Mach number, and temperature including limiting streamlines, shows that the blade tip water injection could help in reducing low energy region downstream of the Shockwave and strength of the tip leakage vortex with the compressor operating at its rotating stall boundary condition. The extent of reduction depends on the droplet size, injection fiow rate, and its velocity. Furthermore, results show that combined case of the blade tip water injection and the wet compression could provide better stall margin enhancement than the blade tip water injection case.

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“…11,12 It takes advantage of the large amount of latent heat of evaporative water to cool the air. Researches showed 1% of water injection increased the gas turbine power up to 10% and thermal efficiency to 3%.…”

Section: Introductionmentioning

confidence: 99%

Performance improvement of a high pressure ratio centrifugal compressor by integrated cooling

Moosania

Zheng

2016

Proceedings of the Institution of Mechanical Engineers, Part G:

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Centrifugal compressors with high pressure ratio have been widely used in small gas turbines, industrial compressors and turbochargers. High mechanical stress and high temperature of the impeller and large compression power required are the key factors that limit the pressure ratio achieved by centrifugal compressors. Cooling is an effective way to reduce the required compression power and the impeller temperature and it is widely used in gas turbines and industrial compressors. In this work, a cooling method named integrated cooling was employed in a high pressure ratio centrifugal compressor. The effects of the integrated cooling on the compressor performance were studied by three-dimensional steady simulation with conjugate heat transfer method using ANSYS CFX commercial solver. It is found that integrated cooling is capable of improving the compressor performance with respect to pressure ratio, efficiency, compression power as well as the impeller maximum temperature. With a cooling temperature of 300 K, the pressure ratio increased by 11.0% and efficiency by about 2.44% at the design condition. Besides, the maximum impeller temperature decreased by about 67 K. This considerable improvement of the compressor performance justifies the integrated cooling, which helps to advance the design of high pressure ratio centrifugal compressors.

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Thermodynamic Analyses of Wet Compression Process in the Compressor of Gas Turbine

Cited by 40 publications

References 0 publications

A Numerical Study of Water Injection on Transonic Compressor Rotor Performance

A Numerical Study of Water Injection on Transonic Compressor Rotor Performance

The Effects of Wet Compression and Blade Tip Water Injection on the Stability of a Transonic Compressor Rotor

Performance improvement of a high pressure ratio centrifugal compressor by integrated cooling

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