Numerical analysis of hydrogen fuel scramjet combustor with turbulence development inserts and with different turbulence models

A plate heat exchanger with a dimple pattern heat plate has a large number of dimples. The shape of dimples defines the characteristics of the plate heat exchanger. Although such heat exchangers have become increasingly popular due to their beneficial characteristics, knowledge of the flow characteristics in such kind of channel is poor. A good knowledge of the flow conditions inside of such channel is crucial for the successful and efficient development of new products. In this paper single-phase water flow in dimple pattern plate heat exchanger was investigated with application of computational fluid dynamics and laboratory experiments. Numerical analysis was performed with two turbulence models, Realizable - with enhanced wall treatment function and - SST. The first predicts a slightly smaller pressure drop and the second slightly larger compared to the results of laboratory measurements. Our research found that despite the relatively low velocity of the fluid, turbulent flow occurs in the channel due to its shape. We also found that there are two different flow regimes in the micro plate heat exchanger channel. The first regime is the regime that dominates the heat transfer, and the second is the regime where a recirculation zone appears behind the brazing point, which reduces the surface for heat transfer. The size of the second regime does not change significantly with the velocity of the fluid in the volume considered.

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Comparison of Various RANS Models for Impinging Round Jet Cooling From a Cylinder

Journal of Heat Transfer ◽

10.1115/1.4043304 ◽

2019 ◽

Vol 141 (6) ◽

Cited By ~ 3

Author(s):

Ketan Atulkumar Ganatra ◽

Dushyant Singh

Keyword(s):

Heat Transfer ◽

Numerical Analysis ◽

Turbulence Model ◽

Three Dimensional ◽

Turbulence Models ◽

Jet Impingement ◽

Target Surface ◽

Point Of View ◽

Nozzle Diameter ◽

Round Jet

The numerical analysis for the round jet impingement over a circular cylinder has been carried out. The v2f turbulence model is used for the numerical analysis and compared with the two equation turbulence models from the fluid flow and the heat transfer point of view. Further, the numerical results for the heat transfer with original and modified v2f turbulence model are compared with the experimental results. The nozzle is placed orthogonally to the target surface (heated cylindrical surface). The flow is assumed as the steady, incompressible, three-dimensional and turbulent. The spacing between the nozzle exit and the target surface ranges from 4 to 15 times the nozzle diameter. The Reynolds number based on the nozzle diameter ranges from 23,000 to 38,800. From the heat transfer results, the modified v2f turbulence model is better as compared to the other turbulence models. The modified v2f turbulence model has the least error for the numerical Nusselt number at the stagnation point and wall jet region.

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Assessment of different turbulence models in simulating axisymmetric flow in suddenly expanded nozzles

International Journal of Engineering & Technology ◽

10.14419/ijet.v7i3.29.18804 ◽

2018 ◽

Vol 7 (3.29) ◽

pp. 243

Author(s):

Sher Afghan Khan ◽

Mir Owais Ali ◽

Miah Mohammed Riyadh ◽

Zahid Hossen ◽

Nafis Mahdi Arefin

Keyword(s):

Numerical Simulation ◽

Numerical Analysis ◽

Mach Number ◽

Numerical Simulations ◽

Axisymmetric Flow ◽

Turbulence Models ◽

Experimental Results ◽

Nozzle Flow ◽

Axisymmetric Nozzle ◽

Good Agreement

A numerical simulation was carried out to compare various turbulence models simulating axisymmetric nozzle flow past suddenly expanded ducts. The simulations were done for L/D = 10. The convergent-divergent nozzle has been modeled and simulated using the turbulence models: The Standard k-ε model, The Standard k-ω model and The SST k-ω model. Numerical simulations were done for Mach numbers 1.87, 2.2, and 2.58 and the nozzles were operated for NPRs in the range from 3 to 11. From the numerical analysis it is apparent that for a given Mach number and effect of NPR will result in maximum gain or loss of pressure. Numerical results are in good agreement with the experimental results.

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Heat Transfer Performance of Fan-Shaped Film Cooling Holes: Part II—Numerical Analysis

Volume 4: Heat Transfer, Parts A and B ◽

10.1115/gt2010-22809 ◽

2010 ◽

Cited By ~ 5

Author(s):

C. Bianchini ◽

B. Facchini ◽

L. Mangani ◽

M. Maritano

Keyword(s):

Heat Transfer ◽

Heat Transfer Coefficient ◽

Numerical Analysis ◽

Transfer Coefficient ◽

Film Cooling ◽

Turbulence Models ◽

Companion Paper ◽

Operating Conditions ◽

Heated Wall ◽

Adiabatic Effectiveness

Fan-shaped holes are widely used to provide better cooling performances than cylindrical holes over a large range of different operating conditions. Main advantages of such solution include a reduced amount of cooling air for the same performance, increased part lifetime and fewer required holes. As the overall cooling performance of such holes is strictly related to the adiabatic effectiveness and heat transfer coefficient (HTC) increase due to the coolant injection, both issues should be investigated. A numerical analysis has been conducted on a laidback fan-shaped film cooling hole onto a flat plate with the aim of investigating the increase of heat transfer. A steady-state RANS analysis was performed at two different blowing ratios (1.25 and 2.5) with imposed heat flux on the heated wall reproducing the same conditions as in the experimental tests presented in the companion paper. Despite no temperature difference was imposed between main gas and coolant flow, adiabatic effectiveness maps were extracted from tracing distribution over the plate. Performances of four different eddy viscosity turbulence models have been tested: the Two-Layer model by Rodi both in the isotropic original formulation and with an anisotropic algebraic correction based on DNS data fitting as firstly proposed by Lakheal, the k–ω SST by Menter and the ν2–f by Durbin. All calculations were conducted with a 3D unstructured pressure-based compressible solver based on the open-source OpenFOAM® CFD platform. A detailed analysis of both the predicted flow field and thermal distribution in the domain was presented. The obtained results were compared with the experimental measurements showed in the companion paper both in terms of wall heat transfer coefficient and adiabatic effectiveness.

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