Gaseous film cooling at various degrees of hot-gas acceleration and turbulence levels

Carlson, L. W.; Talmor, Eliyahu

doi:10.1016/0017-9310(68)90048-3

Cited by 33 publications

(4 citation statements)

References 18 publications

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“…In the early part of the experimental study, the inlet conditions of the test section were checked. Since the boundary layer thickness upstream of injection and the turbulence intensity in the flow field can influence the film cooling process (Carlson and Talmor (1968), Paxson and Mayle (1989), Sakata and Shindo (1991), Seban (1960a)), these quantities were documented. Pitot tube velocity measurements upstream of the slot lip were performed.…”

Section: Resultsmentioning

confidence: 99%

Film Cooling Effectiveness and Heat Transfer Coefficients for Slot Injection at High Blowing Ratios

Bittlinger

Schulz

Wittig

1994

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

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In continuation of earlier studies comparing heat transfer results for flow over a backward facing step and a jet in crossflow, a comprehensive data base for slot film cooling is presented. Specifically, heat transfer measurements adjacent to the injection slot for high blowing ratios were of interest. The heat transfer distributions for these conditions are of increasing significance in modern combustor liners. The new data base includes velocity and temperature profile measurements, adiabatic wall temperature and heat transfer measurements and will serve as a data base for testing newly developed numerical models. t = lip thickness see Eq. 6 i = inflow Presented at the International Gas Turbine and Aeroengine Congress and Exposition

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Section: Resultsmentioning

confidence: 99%

Film Cooling Effectiveness and Heat Transfer Coefficients for Slot Injection at High Blowing Ratios

Bittlinger

Schulz

Wittig

1994

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

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“…In all these studies the efficiency of film cooling was measured under so-called ideal conditions, and most authors singled out three zones: an initial zone, a transition zone, and a main zone, with the efficiency being a different function of m, | l~e s, and x/s in each. Only a few studies [5][6][7][8][9][10] have dealt with the effect of a longitudinal pressure gradient on the cooling efficiency, as such a gradient may cause both streams in actual turbines to mix during film cooling.…”

Section: T O --T~mentioning

confidence: 99%

Efficiency of film cooling in a curvilinear channel between guide blades

Zolotorov

Zysin

Nikolaev

1973

Journal of Engineering Physics

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“…(12) and respectively. Equations (11) and (12) are special cases of Equation (13) for accelerating flow in rectangular channels. However, the use of Equatioq (13) requires knowledge of local pressure-ratio gradients.…”

Section: Data Presentation a N D Correlationmentioning

confidence: 99%

“…Fur the former ( l o ) , the film cooling effectiveness along n straight, nonconverging wall was mildly affected t~y the convergence angle of the opposing wall. However, recent investigations of film cooling along converging walls (11) indicate a drastic effect of convergence angle on film cooling effectiveness leading to a different type of correlation. A similar trend without film cooling may certainly be expected.…”

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confidence: 99%

Heat transfer from boundary layers undergoing an acceleration induced reverse transition

Talmor

Weber

1970

AIChE Journal

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An experimental and analytical investigation of heat transfer in an acceleration induced transitional flow regime is presented. A previously developed criterion for the onset of reverse transition of turbulent boundary layers is combined with a theory of forward transition to derive the effect of free-streom turbulence intensity on the critical value of an acceleration parameter for two initial velocity profiles within the turbulent boundary layer. The results are consistent with experimental observations. Local heot transfer measurements were obtained along converging walls of rectangular flow channels having convergence angles of 45, 60, and 70 deg. Free-,stream turbulence (1.6 to 11 %) was induced by grids upstream of the start of convergence, and the local Reynolds number were varied by variation in channel size and stagnation pressures (200 to 500 Ib./rq.in. abs.) at a gas stagnation temperature of 1,500"R.The results indicate a two-stage reverse transition process along the converging wall with a forword transition between the two stages of reverse transition. The local Nusselt numbers ob- Considerable experimental and analytical efforts have been expended for proper prediction of convective heat transfer coefficients in rapidly accelerating flows. A fair degree of success prevails if the boundary layer is either turbulent (1, 2) or laminar ( 3 ) . However, recent investigations at high rates of acceleration indicate that the boundary layer may be turbulent at the start of convergence but reverts to a transitional or near laminar state toward the sonic point (4, S), The process of reverse transition is seldom complete; that is, truly laminar heat transfer levels are seldom realized.For the transitional flow regime (between the turbulent and laminar with characteristics of neither), the velocity profile within the boundary layer and its associated shear stress relation cannot be described in a universal manner. Therefore, predictions of heat transfer coefficients for this flow regime are lacking, so that emphasis has to be placed on experimental or visual observations.The observed reduction in rocket nozzle heat transfer below that typical of a turbulent boundary layer (through the process of reverse transition) provides a strong motive to seek a method by which the phenomenon of reverse transition can be incorporated into design criteria. Two basic problems are involved: prediction of the onset of reverse transition (or laminarization) of a turbulent boundary layer, and estimation of heat transfer coefficients in the transitional flow regime.Several basic experimental investigations of acceleration induced reverse transition of turbulent boundary layers have been reported (6 to 9). However, the boundary layers investigated were developed on straight, nonconverging, side plates with the stream-by-stream pressure gradient being controlled by adjustments of an opposite converging wall, Such data are hardly applicable for the design of converging walls. This is well reflected by comparisons of the effect of ...

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Gaseous film cooling at various degrees of hot-gas acceleration and turbulence levels

Cited by 33 publications

References 18 publications

Film Cooling Effectiveness and Heat Transfer Coefficients for Slot Injection at High Blowing Ratios

Film Cooling Effectiveness and Heat Transfer Coefficients for Slot Injection at High Blowing Ratios

Efficiency of film cooling in a curvilinear channel between guide blades

Heat transfer from boundary layers undergoing an acceleration induced reverse transition

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