Investigation of influencing factors of hot streaks migration in high pressure stage of a vaneless counter-rotating turbine

Zhao, Qingjun; Wang, Huishe; Tang, Fei; Zhao, Xiuli; Xu, Jianzhong

doi:10.1007/s11431-008-0024-x

Cited by 6 publications

(8 citation statements)

References 19 publications

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“…In the previous work [3], iterations between airfoil blading and numerical analysis of 3D steady viscous flow were used in the designing process to solve the problem, and the final blade-to-blade passage was an equivalent convergentdivergent passage. Numerical simulation and experiment results [3,[5][6][7] showed that the designed blade was usable and far from perfect. The problem is that the iteration between airfoil blading and 3D calculations is not easy to put into practice, because it needs the designer to do a lot of iteration work, but even though it still lacks accuracy.…”

Section: Methods On Choosing Exit-to-throat Width Ratio For 3d Transonmentioning

confidence: 99%

“…As a result, convergent-divergent shape was adopted in the HPT rotor design [3]. Numerical simulation and experiment results [3,[5][6][7] showed that the designed blade could be used but it was far from perfect. The problem is that it requires the designer to do a lot of iteration work between airfoil blading and 3D calculations until the final blade is got.…”

Section: Purpose Of the Studymentioning

confidence: 99%

“…The flows in originally designed VCRT have been calculated, and the accuracy of the computation is acceptable as in tests by Zhao [5][6][7].…”

Section: Meshesmentioning

confidence: 99%

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Influence of exit-to-throat width ratio on performance of high pressure convergent-divergent rotor in a vaneless counter-rotating turbine

Zhang

Wang

Wei

et al. 2011

Sci. China Technol. Sci.

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This paper describes the redesign of a high pressure rotor (with exit Mach number around 1.5) for the vaneless counter-rotating turbine by choosing adequate exit-to-throat width ratio. Based on the previous design analysis and test results, effects of the exit-to-throat width ratio on the performance of the transonic turbine cascade were proposed. In order to investigate the influence of the exit-to-throat width ratio on the performance of the turbine cascade, a flow model of the convergent-divergent turbine cascade was constructed by using the theory of Laval nozzle. Then a method on how to choose the adequate exit-to-throat width ratio for the turbine cascade was proposed. To validate the method, it was used to calculate the adequate exit-to-throat width ratio for the high pressure rotor of the vaneless counter-rotating turbine. The high pressure turbine rotor was redesigned with the new exit-to-throat width ratio. Numerical simulation results show that the isentropic efficiency of the redesigned vaneless counter-rotating turbine under the design condition has increased by 0.9% and the efficiencies under the off-design conditions are also improved significantly.On the original design, a group of compressional waves are created from the suction surface after about 60% axial chord in the high pressure turbine rotor. While on the new design the compressional waves are eliminated. Furthermore, on the original design, the inner-extending waves first impinge on the next high pressure turbine rotor suction surface. Its reflection is strong enough and cannot be neglected. However on the new design the inner-extending waves are weakened or even eliminated.Another main progress is that the redesigned high pressure turbine rotor is of practical significance. In the original rotor, a part of the blade (from 60% axial chord to the trailing edge) is thin leading to the intensity problem and difficult arrangement of the cooling system. In the new design, however, the thickness distribution of the rotor airfoil along the chord is relatively reasonable. The intensity of the rotor is enhanced. It is possible to arrange the cooling system reasonably. exit-to-throat width ratio, counter-rotating turbine, transonic turbine, high pressure rotor Citation:Zhang L, Wang H S, Luo W W, et al. Influence of exit-to-throat width ratio on performance of high pressure convergent-divergent rotor in a vaneless counter-rotating turbine.

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Section: Methods On Choosing Exit-to-throat Width Ratio For 3d Transonmentioning

confidence: 99%

Section: Purpose Of the Studymentioning

confidence: 99%

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Influence of exit-to-throat width ratio on performance of high pressure convergent-divergent rotor in a vaneless counter-rotating turbine

Zhang

Wang

Wei

et al. 2011

Sci. China Technol. Sci.

Self Cite

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“…To control the high-temperature, a cooling system has to be used. Optimum design of the cooling system requires the knowledge of migration characteristics of the hot jet and of parallel air flow [3]. There have been many studies regarding impingement of jets on an endplate [4] [5].…”

Section: Introductionmentioning

confidence: 99%

Computational Study on Aerodynamic and Thermal Characteristics of a Hot Jet in Parallel Flow

Das¹,

Jungio²,

Haritha³

et al. 2017

OJFD

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The study of the migration characteristics of turbulent jets has become relevant as they are used in a variety of engineering devices and are encountered in combustion, chemical processes, and processes involving cooling, mixing, and drying. In several applications, especially in the case of hot streaks in gas turbines, the knowledge of mixing phenomena becomes crucial from a design perspective. The purpose of this study is to look into the characteristics of a round hot jet in a parallel air flow. A jet of hot air injected through a nozzle into a flow of cold air has been considered. Numerical simulations were carried out with different hot jet temperatures and two different Reynold's numbers, thus aiming at understanding the effect of initial conditions on the mixing of the jet. The temperature profiles were studied at different sections downstream of the nozzle. The results are presented in non-dimensional form.

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“…It is obvious that the VCRT will be widely adopted in real aero-engines in the future. From the 1950s, counter-rotating turbines have been carefully investigated [1][2][3][4][5][6][7][8] . Researchers focus on aerodynamic design of CRT, flow field analysis in CRT, and so on.…”

mentioning

confidence: 99%

Experimental investigation on unsteady pressure fluctuation of rotor tip region in high pressure stage of a vaneless counter-rotating turbine

Zhao

Liu

Wang

et al. 2009

Sci. China Ser. E-Technol. Sci.

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An experimental investigation has been performed to study the unsteady pressure fluctuation of rotor tip region in high pressure stage of a vaneless counter-rotating turbine. The experiment is carried out on a blow-down short duration turbine facility. The investigation indicates that the blow-down short duration turbine facility is capable of substituting continuous turbine facilities in most turbine testing. Through this experimental investigation, a distinct blade-to-blade variation is observed. The results indicate that the combined effects of vane wake, tip leakage flow, complicated wave systems and rotor wake induce the remarkable blade-to-blade variations. The results also show that the unsteady effect is intensified along the flow direction.counter-rotating turbine, pressure fluctuation, unsteady effect, short duration experimentIn the recent few years, more and more attentions have been paid to counter-rotating turbine (CRT) because it can offer some significant benefits compared with conventional two-stage turbine, such as the elevated thrust-to-weight ratio of aero-engine, the improved performance of aircraft, and so on. At present, 1-1 stage counter-rotating turbine has been used in some advanced active duty aero-engines, and vaneless counter-rotating turbine (VCRT, 1-1/2 stage counter-rotating turbine), which is composed of a highly loaded single stage high pressure turbine (HPT) and a vaneless counter-rotating single stage low pressure turbine (LPT), has been also applied in some up-to-date test engines in Euro-American developed countries. It is obvious that the VCRT will be widely adopted in real aero-engines in the future. From the 1950s, counter-rotating turbines have been carefully investigated [1][2][3][4][5][6][7][8] . Researchers focus on aerodynamic design of CRT, flow field analysis in CRT, and so on. These conclusions drawn by predecessors drive the development of the CRT technology.Some of approaches to increase efficiency or decrease loss need to be applied to enhancing specific work and reducing fuel consumption of gas turbine engines. In modern high load turbines, the loss induced by tip clearance leakage flow is remarkable. A number of investigations on tip clearance leakage flow have been performed by many researchers [9][10][11][12][13][14][15][16][17][18][19][20][21][22] to decrease the flow loss. Farokhi [9] analyzed the tip clearance loss in an axial flow turbine and proposed a model that accounts for tip pressure loading, relative wall motion and stage characteristics. A simple two-dimensional model for the calculation of the leakage flow over the blade tips of axial turbine was described in ref.[10]. In the model, the importance of pressure gradients along the blade chord was emphasized as a major factor influencing the tip leakage flow. Liu and Bozzola [11] investigated the tip clearance flow structures, leakage vortex, flow underturning, and the effect of the tip clearance on blade loading and losses by means of a three-dimensional code. The predicted

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Investigation of influencing factors of hot streaks migration in high pressure stage of a vaneless counter-rotating turbine

Cited by 6 publications

References 19 publications

Influence of exit-to-throat width ratio on performance of high pressure convergent-divergent rotor in a vaneless counter-rotating turbine

Influence of exit-to-throat width ratio on performance of high pressure convergent-divergent rotor in a vaneless counter-rotating turbine

Computational Study on Aerodynamic and Thermal Characteristics of a Hot Jet in Parallel Flow

Experimental investigation on unsteady pressure fluctuation of rotor tip region in high pressure stage of a vaneless counter-rotating turbine

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