Experimental and Numerical 3-D Investigations of the Flow Field Behind the Trailing Edge of a Cooled Turbine Guide Vane

Bohn, Dieter; Behnke, Klaus

doi:10.1115/96-ta-027

Cited by 4 publications

(4 citation statements)

References 2 publications

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“…The exit Mach number is lower than the design exit Mach number as the results are to be compared to former investigations with trailing edge ejection (Table 1). For this former configuration, the exit Mach number was limited (0 0.75 for measurement reasons (Bohn et_ al, 1996a).…”

Section: Operating Condmonsmentioning

confidence: 99%

Experimental and Numerical Conjugate Flow and Heat Transfer Investigation of the Influence of Density Ratio and Blowing Ratio on the Film-Cooling Efficiency of a First Stage Turbine Guide Vane

Bohn

Rungen

1999

Volume 3: Heat Transfer; Electric Power; Industrial and Cogeneration

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A modem nozzle guide vane with showerhead cooling is investigated. The showerhead design consists of four rows of ejection holes at the leading edge in the stagnation region and has been worked out on the basis of a former design with only two rows. The experimental analysis is performed in a cold-air test turbine by means of LDV. In order to overcome the thermal limitations of the test rig, the heat transfer analysis is performed with CHT-Flow, a numerical method that has been developed at the Institute of Steam and Gas Turbines and that works in a conjugate manner. This means that no thermal boundary conditions such as heat transfer coefficients have to be described on the vane surface for thermal analysis. The first part of the investigation deals with the aerodynamics. At first, air is used as a cooling fluid leading to a density ratio of Πρ = 1.2. Then, in order to take density effects into account in the experiments. CO2 is used as a cooling gas providing a density ratio Πρ = 1.8 representative for modern engine operating conditions. The results are compared to the simulations. It is shown that the cooling gas does not penetrate the main flow as far under realistic density ratios. Thus, the aerodynamic losses are reduced and there is better attachment of the cooling film to the airfoil. The second part analyses the heat transfer. It is shown that lowering the blowing ratio has different influences on the material temperature locally. On the suction side, the cooling gas film attachment is enhanced and the surface temperature is lowered. In contrast, the surface temperature rises slightly on the pressure side.

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Section: Operating Condmonsmentioning

confidence: 99%

Experimental and Numerical Conjugate Flow and Heat Transfer Investigation of the Influence of Density Ratio and Blowing Ratio on the Film-Cooling Efficiency of a First Stage Turbine Guide Vane

Bohn

Rungen

1999

Volume 3: Heat Transfer; Electric Power; Industrial and Cogeneration

Self Cite

View full text Add to dashboard Cite

show abstract

“…The exit Mach number is lower than the design exit Mach number as the results are to be compared to former investigations with trailing edge ejection. For this former configuration, the exit Mach number was limited to 0.75 for measurement reasons (Bohn et. al, 1996a).…”

Section: Measurement Gridmentioning

confidence: 99%

Experimental and Numerical Conjugate Investigation of the Blowing-Ratio Influence on the Showerhead Cooling Efficiency

Bohn

Kusterer

Rungen

1998

Volume 4: Heat Transfer; Electric Power; Industrial and Cogeneration

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This paper presents the experimental investigation of the flow and the numerical analysis of the flow and heat transfer in a turbine guide vane with showerhead cooling for two different blowing ratios. The aerodynamic results are compared with those of the experiments. Starting with a showerhead design of two rows of ejection holes, two additional rows have to be used in an enhanced design due to hot gas contact in the leading edge area. Thus, the cooling gas mass flow is doubled when keeping the blowing ratio constant at m = 1.5. Lowering the amount of cooling gas needed whilst still guaranteeing sufficient cooling is the motivation for the analysis of the influence of a lower blowing ratio on the cooling efficiency. The investigated blowing ratios are m = 1.5 and m = 1.0. The experiments are conducted using a non-intrusive LDA technique. The numerical results are gained with a conjugate heat transfer and flow computer code that has been developed at the Institute of Steam and Gas Turbines. The results show that the blowing ratio has to be chosen carefully as the leading edge flow pattern and the heat transfer are strongly influenced by the blowing ratio. Lower blowing ratios lead to a better attachment of the cooling film and thus they hardly disturb the main flow. With the lower blowing ratio, the material temperature increases up to 1.5% of the total inlet temperature in the leading edge area on the pressure side, whereas it decreases locally for about 0.8% for the lower blowing ratio on the suction side. This is due to the enhanced attachment of the cooling gas film.

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“…Initially, studies concentrated on the fundamental characteristics and flow loss processes of partial admission turbines [4,5]. The flow channel structure [6,7], nozzle arrangement [8,9], and blade parameters [10,11] were determined to be the key elements impacting the performance of partial admission turbines. Researchers generally concurred that, in terms of flow channel structure, reducing the axial clearance between the nozzle and rotor within a suitable range can result in greater efficiency [12,13] and with decreasing mass flow rate, the efficiency and optimum speed ratio decline.…”

Section: Introductionmentioning

confidence: 99%

Compressed air energy storage system: Effect of variable relative stator installation angle on nozzle governing turbine performance

Guan,

Li,

Zhu

et al. 2024

J. Phys.: Conf. Ser.

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The air storage pressure of compressed air energy storage system gradually decreases during the process of energy release, and a reasonable air distribution method for the turbine is required to make the turbine work efficiently in this process. In this paper, based on the single nozzle governing method, the effect of the variation of the full circumferential relative stator installation angle on the system performance improvement under the rated output work condition is investigated. It is shown that the specific work of the variable relative stator installation angle can be improved by up to 6.3 % relative to the design stator installation angle and up to 15.7 % relative to the throttle governing method under the base pressure of 10.0 MPa. With the same absence of throttling losses, the specific work of 3-nozzle inlets method is higher than that of 4-nozzle inlets method, and the turbine internal losses are reduced by 10.6 %. This study provides a theoretical basis for the design, optimization and operation control of nozzle governing turbines.

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Experimental and Numerical 3-D Investigations of the Flow Field Behind the Trailing Edge of a Cooled Turbine Guide Vane

Cited by 4 publications

References 2 publications

Experimental and Numerical Conjugate Flow and Heat Transfer Investigation of the Influence of Density Ratio and Blowing Ratio on the Film-Cooling Efficiency of a First Stage Turbine Guide Vane

Experimental and Numerical Conjugate Flow and Heat Transfer Investigation of the Influence of Density Ratio and Blowing Ratio on the Film-Cooling Efficiency of a First Stage Turbine Guide Vane

Experimental and Numerical Conjugate Investigation of the Blowing-Ratio Influence on the Showerhead Cooling Efficiency

Compressed air energy storage system: Effect of variable relative stator installation angle on nozzle governing turbine performance

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