The computation of turbulent flow through stationary and rotating U-bends with rib-roughened surfaces

Iacovides, Hector

doi:10.1002/(sici)1097-0363(19990415)29:7<865::aid-fld821>3.0.co;2-m

Cited by 17 publications

(15 citation statements)

References 12 publications

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“…In this arrangement all the variables are stored at the control volume cell centre and the same control volume is employed for integration of all the conservation equations. A bounded version of QUICK scheme, developed by Iacovides [14], is used for the approximation of convective terms. In QUICK scheme, depending on the flow direction, the value of unknown dependent variable at each face of control volume is evaluated from a quadratic polynomial which passes through a grid point downstream and two grid points upstream of each face.…”

Section: Numerical Methods Aspects and Boundary Conditionsmentioning

confidence: 99%

“…The predicted local heat transfer coefficients of both turbulence models were lower than the measured values, but the 2-layer DSM returned a more realistic profile for the local Nusselt number. Iacovides [14] also predicted the flow development in a rotating duct with staggered ribs, using 2-layer models. Comparisons with the LDA data of Iacovides et al [15] showed that both models reproduce the Coriolis effect on the mean flow, but the DSM model was in closer agreement with the measured change in turbulence levels from the suction to the pressure side of the rotating duct.…”

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confidence: 99%

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Prediction of Flow and Heat Transfer through Stationary and Rotating Ribbed Ducts Using a Non-linear k−ε Model

Raisee

Naeimi

Alizadeh

et al. 2008

Flow Turbulence Combust

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The present paper deals with the prediction of three-dimensional fluid flow and heat transfer in rib-roughened ducts of square cross-section, which are either stationary, or rotate in orthogonal mode. The main objective is to assess how a recently developed variant of a cubic non-linear k-ε model (proposed by Craft et al. Flow Turbul Combust 63:59-80, 1999) can predict three-dimensional flow and heat transfer characteristics through stationary and rotating ribbed ducts. The present paper discusses turbulent air flow and heat transfer through two different configurations, namely: (I) a stationary square duct with "in-line" normal and (II) a square duct with normal ribs in a "staggered" arrangement under stationary and rotating conditions, with the axis of rotation normal to the flow direction and parallel to the ribs. In this paper the flow and thermal predictions of the linear k-ε model (EVM) are also included, as a set of baseline predictions. The mean flow predictions show that both linear and non-linear k-ε models can successfully reproduce most of the measured data for stream-wise and cross-stream velocity components. Moreover, the non-linear model is able to produce better results for the turbulent stresses. The heat transfer predictions show that both EVM and NLEVM2, the more recent variant of the non-linear k-ε, with the algebraic length-scale correction term, overestimate the measured Nusselt numbers for both geometries examined. While the EVM with the differential length-scale correction term underestimates heat transfer levels, the Nusselt number predictions with the NLEVM2 and the 'NYP' term are in close agreements with the measured data. Comparisons with our earlier work, Iacovides 122 Flow Turbulence Combust (2009) 82:121-153 and Raisee (Int J Heat Fluid Flow, 20:320-328, 1999), show that the NLEVM2 thermal predictions are of similar quality to those of a second-moment closure.

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Section: Numerical Methods Aspects and Boundary Conditionsmentioning

confidence: 99%

mentioning

confidence: 99%

Prediction of Flow and Heat Transfer through Stationary and Rotating Ribbed Ducts Using a Non-linear k−ε Model

Raisee

Naeimi

Alizadeh

et al. 2008

Flow Turbulence Combust

Self Cite

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“…As mentioned earlier, the damping functions shown in (18) and (20), and (21) have been devised with reference to fully developed pipe flows and not specifically for the ribbed passage flows presented in this study. …”

Section: Low-re Dsm Closurementioning

confidence: 99%

“…In the case of the DSM models, the apparent viscosity concept is used to prevent numerical oscillations that arise from the explicit presence of the Reynolds stress gradients in the momentum equations. For the convective discretization of all transport equations, a bounded form of the quadratic upstream interpolation scheme (QUICK) was used, proposed by Iacovides [18]. For a given mesh, the DSM …”

Section: Numerical Aspectsmentioning

confidence: 99%

The computation of flow and heat transfer through an orthogonally rotating square‐ended U‐bend, using low‐Reynolds‐number models

Nikas

Iacovides²

2006

International Journal of Numerical Methods for Heat &Amp; Fluid Flow

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We present computations of heat and fluid flow through a square-ended U-bend that rotates about an axis normal to both the main flow direction and also the axis of curvature. Two-layer and low-Reynolds-number mathematical models of turbulence are used at effective-viscosity (EVM) level and also at second-moment-closure (DSM) level. Moreover, two length-scale correction terms to the dissipation rate of turbulence are used with the low-Re models, the original Yap term, and a differential form that does not require the wall distance (NYap). The resulting predictions are compared with available flow and heat transfer measurements of water. While the main flow features are well reproduced by all models, the development of the mean flow within and just after the bend is better reproduced by the low-Re models. Turbulence levels within the rotating U-bend are underpredicted, but DSM models produce a more realistic distribution. Along the leading side, all models overpredict heat transfer levels just after the bend. Along the trailing side, the heat transfer predictions of the low-Re DSM with the NYap, are close to the measurements.

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“…Besserman and Tanrikut [5] evaluated two near-wall shear-stress treatments (wall functions and the two layer wall integration method) in conjunction with the k- formulation of turbulence to assess their ability to predict high local gradients in heat transfer. Iacovides [6] applied the effective viscosity (EVM) and second-moment turbulence models in the computation of flow and heat transfer through rib-roughened passages. Sewall and Tafti [7] presented large eddy simulations of a 180 deg bend in a stationary ribbed duct.…”

Section: Introductionmentioning

confidence: 99%

On numerical simulations of flow and heat transfer of the bend part of a U-duct

Salameh

Sundén

2010

Advanced Computational Methods and Experiments in Heat Transfer XI

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Two dimensional numerical simulations of the flow and temperature fields inside the bend (turn) part of a U duct have been performed. Both the standard and low Reynolds number k- models were used to solve the smooth bend (turn) part and ribbed bend (turn) part, respectively. For the standard k- model, the wall function approach was used at the near wall region where the log-law was assumed to be valid, whereas the modelling damping functions were used in the low Reynolds number model. In the case of the ribbed bend (turn) part, two approaches were used, the total approach and an approach based on periodic flow condition. The details of the duct geometry were as follows: the cross section area of the straight part is 5050 mm 2 , the inside length of the bend part 240 mm, the cross section area of the rib is 55 mm 2 and the rib height-tohydraulic diameter ratio, e/Dh, is 0.1. The results are compared with experimental data obtained for the same conditions.

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The computation of turbulent flow through stationary and rotating U-bends with rib-roughened surfaces

Cited by 17 publications

References 12 publications

Prediction of Flow and Heat Transfer through Stationary and Rotating Ribbed Ducts Using a Non-linear k−ε Model

Prediction of Flow and Heat Transfer through Stationary and Rotating Ribbed Ducts Using a Non-linear k−ε Model

The computation of flow and heat transfer through an orthogonally rotating square‐ended U‐bend, using low‐Reynolds‐number models

On numerical simulations of flow and heat transfer of the bend part of a U-duct

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