Turbulence model and validation of air flow in crossflow turbine nozzle

Pujowidodo, Hariyotejo; Siswantara, Ahmad Indra; Budiarso,; Gunadi, Gun Gun Ramdlan; Daryus, Asyari

doi:10.1063/1.5050007

Cited by 3 publications

(3 citation statements)

References 3 publications

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“…This study found that the Standard k-ε gave an effective prediction about the pressure and velocity of air in the wind tunnel as studied by Ramdlan et al, [22]. Whereas in case of cross flow turbine nozzle, Pujowidodo et al, [23] found that the RSM model has a good agreement than standard k-ε and RNG k-ε. The RNG k-є turbulence model had been used by Koten et al, [24] to improve the ability k-є Standard for predicting recirculating flows and complex shear layers in ultralow emission study of compressed bio gas-diesel dual fuel engine.…”

Section: Introductionmentioning

confidence: 72%

A New Modified k-ɛ Turbulence Model for Predicting Compressible Flow in Non- Symmetrical Planar-Curvature Converging-Diverging Supersonic Nozzle

Pujowidodor¹,

Siswantara²,

Budiarso³

et al. 2020

CFDL

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Convergent-Divergent (CD) nozzle of a compressible fluid is a common device to accelerate fluid flow to a higher supersonic speed and to direct or modify the fluid flow. CD nozzle has been applied in wide range of fluid equipment such as turbine power, chemical mixing equipment, turbojet engine, and rocket. The performance of CD nozzle is strongly affected by its geometry at certain pressure ratio and the flow characteristic. In the case of complicated flow phenomena within a supersonic flow, especially in the turbulence flow, many studies use the computational simulation to obtain the detailed behavior and properties of flow. However, the k-epsilon turbulence model has limitations in predicting the effect of dissipation due to the viscous friction. This study aims to propose the new modified k-ε turbulence model in planar-curvature Convergent-Divergent (CD) nozzle of a compressible fluid. Two equations model of modified Standard k-ε for predicting the compressible flow within planar-curvature CD nozzle was discussed. The simulation model was run in 2D and steady, while fluid was assumed as an ideal gas with domain size was 0.65 m length, 0.071 m width. In addition, it has been discretized in 3510 structured independent grid cells. The results depicted that in the divergent section of the nozzle (supersonic region), the fluid expansion caused the change in fluid parameters such as time-average of pressure, temperature, density, and velocity. This study found that the expanded cross-sectional area with non-symmetrical planar curvature affected the turbulence behavior and properties. Furthermore, the new modified constants of c2 in dissipation equation and cμ of eddy viscosity model could give a better prediction than the original constant of the k-ε turbulence model.

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Section: Introductionmentioning

confidence: 72%

A New Modified k-ɛ Turbulence Model for Predicting Compressible Flow in Non- Symmetrical Planar-Curvature Converging-Diverging Supersonic Nozzle

Pujowidodor¹,

Siswantara²,

Budiarso³

et al. 2020

CFDL

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“…Numerical simulations can help save time and lower costswhen conducting experiments (Ramdlan et al, 2016;Pujowidodo et al, 2018). Here, modelling wasdone by attaching 20 pipes in the upright channel as shownin Figure 1a.…”

Section: Methodsmentioning

confidence: 99%

Characteristics of Air Flow and Heat Transfer in Serpentine Condenser Pipes with Attached Convection Plates in Open Channel

Susanto

Alhamid²,

Nasruddin

et al. 2020

IJTech

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Many efforts have been made to reduce the energy consumption of household refrigerators. One method is to place the pipe condenser to increase the rate of heat release. This numerical study examines the effect of changing the gap ratio on the flow characteristics and natural convection heat transfer of 20 pipes attached vertically to the convection plate with aluminum foil coating. The gap ratio was varied between 1.05 and 4.20 using ANSYS-FLUENT software to obtain velocity vector, temperature contour, tangential velocity, and local Nusselt number, both inside and outside the channel. With the change in gap ratios from 1.05 to 2.10, the rate of heat transfer increased significantly, reaching 2.2% while tangential velocity also increased considerably. At gap ratios of 3.15 and 4.20, the rate of heat transfer increased more gradually, local Nusselt number increased slightly where the influence of convection walls was smaller, and tangential velocity showed a very small increase. Flow characteristics were similar, with air flowing upward across the inner and outer channels.

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“…It also has been used by several researchers with good simulation results. Moreover, researchers are familiar with the appearance of this software, making it easier to do simulations [28,[30][31][32]. The main simulation objective is to study the effects of changing the 𝜎 𝜀 value from 0.5 to 1.5 on the recirculating flow prediction performance using the Standard 𝑘 − 𝜀 turbulence model.…”

Section: Modeling Of Turbulent Recirculating Flow In a Crossflow Wate...mentioning

confidence: 99%

Optimization of inverse-Prandtl of Dissipation in standard k-ε Turbulence Model for Predicting Flow Field of Crossflow Turbine

Widiawaty

Siswantara

Gunadi

et al. 2022

CFDL

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Despite the successful use of the Standard model in simulating turbulent flow for many industrially relevant flows, the model is still less accurate for a range of important problems, such as unconfined flows, curved boundary layers, rotating flows, and recirculating flows. As part of the authors’ effort to extend the model applicability and reliability, this paper aims to study the effects of diffusivity parameter called the turbulent Prandtl number of dissipation rate () on the Standard model performance for predicting recirculating flow in a crossflow water turbine. The value of this parameter was varied from 0.5 to 1.5 in the CFD simulations, and the results were compared to the more sophisticated model, namely the RNG , which has been first qualitatively validated by an experimental result. In addition, the parameter value was also adjusted using the Multi-Linear Regression (MLR) method ranging from 0.42 to 1.5 to complement the CFD simulations. It was observed that reducing the value is effective in minimizing the average deviation of the turbulence properties concerning the RNG model. However, the adjusted model still faces difficulty in accurately predicting the pressure and velocity field. Based on this result, adjusting the constant in the Standard turbulence model has the potential to improve the model performance for modelling recirculating flow in terms of the turbulence properties, but still needs further investigation for the flow properties.

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Turbulence model and validation of air flow in crossflow turbine nozzle

Cited by 3 publications

References 3 publications

A New Modified k-ɛ Turbulence Model for Predicting Compressible Flow in Non- Symmetrical Planar-Curvature Converging-Diverging Supersonic Nozzle

A New Modified k-ɛ Turbulence Model for Predicting Compressible Flow in Non- Symmetrical Planar-Curvature Converging-Diverging Supersonic Nozzle

Characteristics of Air Flow and Heat Transfer in Serpentine Condenser Pipes with Attached Convection Plates in Open Channel

Optimization of inverse-Prandtl of Dissipation in standard k-ε Turbulence Model for Predicting Flow Field of Crossflow Turbine

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