A 3-dimensional, coupled, DNS, heat transfer model and solution for multi-hole cooling

Zhong, Fengquan; Brown, G. T.

doi:10.1016/j.ijheatmasstransfer.2006.09.017

Cited by 14 publications

(9 citation statements)

References 10 publications

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“…Instead of iterating to try to match temperature and heat flux directly at the fluid/solid interface, a mixed boundary condition in the form of ) ( and the coolant flow was used. Details of methodology of the fluid/solid coupling and a mathematical proof of the uniqueness of solutions of the wall temperature can be found in a previous work of the author [8]. The iteration procedure by using heat transfer coefficient as the coupling parameter is proven to be very efficient and converged temperature and heat transfer solutions of the cooled strut can be achieved within 2-3 iteration steps as discussed in the next section.…”

Section: Fluid/solid Heat Transfer Couplingmentioning

confidence: 99%

Three-Dimensional Heat Transfer Analysis and Optimized Design of Actively Cooled Strut for Scramjet Applications

FQ¹,

TY²,

XJ³

et al. 2012

48th AIAA/ASME/SAE/ASEE Joint Propulsion Conference &Amp;amp; Exhibit

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In this paper, a numerical analysis coupling heat transfers of the combustor internal flow, the coolant flow and the strut wall is developed and applied for the optimization of strut cooling using aviation kerosene as coolant at flow conditions corresponding to the combustor entrance condition for Mach 6 scramjet flight. The coupling procedure is tested and proven to be an efficient method of being capable to obtain the converged temperature and heat transfer solutions of the cooled strut within a few iteration steps. Four cooling designs with varied diameter, length and position of the cooling channels are investigated and their improvements on fuel injection and mixing are also verified compared to the wall injection. The kerosene-cooled strut (Strut4) is tested in a Mach 2.5 supersonic tunnel with inlet total temperature and total pressure of 1900K and 1.45MPa respectively for 60 seconds. The damaged part in the upper leading edge of the strut is observed, which is consistent with the result obtained by the numerical analysis.

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Section: Fluid/solid Heat Transfer Couplingmentioning

confidence: 99%

Three-Dimensional Heat Transfer Analysis and Optimized Design of Actively Cooled Strut for Scramjet Applications

FQ¹,

TY²,

XJ³

et al. 2012

48th AIAA/ASME/SAE/ASEE Joint Propulsion Conference &Amp;amp; Exhibit

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“…A special purpose heat transfer tunnel was designed to meet two principal requirements: (1) the duplication of Reynolds number, coolant and free stream density ratio and velocity ratio applicable for ceramic matrix composite (CMC) specimens proposed for a multi-hole cooling system for gas turbine applications; (2) a wide range of Reynolds number to provide both an overlap with DNS calculations at low Reynolds number [4] and also the highest Reynolds number of the applications.…”

Section: The Experimental Facilitymentioning

confidence: 99%

“…(Compared with super-alloy walls with a thermal conductivity of approximately 100 W/m/K, CMC materials have a smaller thermal conductivity of 4$15 W/m/K, but this value is still relatively large compared with many ceramics k < 1 W/m/K.) In their recent detailed numerical study, Zhong and Brown [4] addressed the importance of the backside cooling effect for a multi-hole oxide/oxide specimen and proposed a 3D coupled heat transfer model, which includes all heat transfer processes (except radiative heat transfer) in a multi-hole cooling system. Their DNS solutions show the significant effect of the backside cooling and their predictions of the cooling effectiveness agree well with the experimental results at the same Reynolds numbers and cooling conditions.…”

Section: Introductionmentioning

confidence: 99%

“…at a tunnel temperature of 400 K, a coolant temperature of 167 K and a tunnel pressure of 10 atm. This scaling enables the density 4 and density ratio (ratio of coolant to main-stream) to be the same as for an actual combustor flow. By using the same CMC material and geometry as in the actual combustor liner, the same Reynolds number (based on the characteristic dimension for the geometry of the liner material) can be obtained by adjusting the free stream velocity as follows.…”

Section: Introductionmentioning

confidence: 99%

“…Of course L or dwill vary with the application but the present scaling ensures a matching of the principal parameters, velocity ratio, 3 The flow conditions used here are obtained with reference to proposed working conditions for a future turbine engine combustor, for example, a 2-D Trapped Vortex Combustor. 4 The same density is based on the assumption of a perfect gas.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Experimental study of multi-hole cooling for integrally-woven, ceramic matrix composite walls for gas turbine applications

Zhong

Brown

2009

International Journal of Heat and Mass Transfer

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a b s t r a c tIn this paper, multi-hole cooling is studied for an oxide/oxide ceramic specimen with normal injection holes and for a SiC/SiC ceramic specimen with oblique injection holes. A special purpose heat transfer tunnel was designed and built, which can provide a wide range of Reynolds numbers (10 5 $ 10 7 ) and a large temperature ratio of the primary flow to the coolant (up to 2.5). Cooling effectiveness determined by the measured surface temperature for the two types of ceramic specimens is investigated. It is found that the multi-hole cooling system for both specimens has a high cooling efficiency and it is higher for the SiC/SiC specimen than for the oxide/oxide specimen. Effects on the cooling effectiveness of parameters including blowing ratio, Reynolds number and temperature ratio, are studied. In addition, profiles of the mean velocity and temperature above the cooling surface are measured to provide further understanding of the cooling process. Duplication of the key parameters for multi-hole cooling, for a representative combustor flow condition (without radiation effects), is achieved with parameter scaling and the results show the high efficiency of multi-hole cooling for the oblique hole, SiC/SiC specimen.

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Implicit algebraic model for predicting turbulent heat flux in film cooling flow

Rajabi-Zargarabadi

Bazdidi–Tehrani

2009

Numerical Methods in Fluids

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SUMMARYThe present study addresses a new effort to improve the prediction of turbulent heat flux in the film cooling flow by applying the implicit algebraic flux (IAF) model of Rogers et al. A three-dimensional symmetry case is investigated using a film hole length-to-diameter ratio of 1.75 and an injection angle of 35 • . The low Reynolds number second moment closure (SMC) model with a wall-reflection term is employed for simulating the turbulent flow field right up to the wall. Results obtained from the IAF model are compared with two other algebraic turbulent heat flux models, namely, the simple eddy diffusivity (SED) with a constant turbulent Prandtl number and the generalized gradient diffusion hypothesis (GGDH). Comparisons of the turbulent heat flux components calculated by these models show that the major difference appears in the streamwise turbulent heat flux. These models demonstrate a significant effect on the prediction of film cooling effectiveness. The SED model with a constant prescribed value for the turbulent Prandtl number fails to predict the cooling air spreading in the lateral direction while by employing the GGDH and IAF models, the spreading of the cooling air and the decay of the effectiveness in the core region are reasonably predicted. A combination of the SMC and IAF models for simulating the turbulent flow and heat transfer is capable of predicting the streamwise and lateral film cooling effectiveness in very good agreement with the available experimental data.

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A 3-dimensional, coupled, DNS, heat transfer model and solution for multi-hole cooling

Cited by 14 publications

References 10 publications

Three-Dimensional Heat Transfer Analysis and Optimized Design of Actively Cooled Strut for Scramjet Applications

Three-Dimensional Heat Transfer Analysis and Optimized Design of Actively Cooled Strut for Scramjet Applications

Experimental study of multi-hole cooling for integrally-woven, ceramic matrix composite walls for gas turbine applications

Implicit algebraic model for predicting turbulent heat flux in film cooling flow

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