Problems of simulating tornado-like heat transfer in turbulent flow past a dimpled relief on a narrow channel wall

Исаев, С. А.; Leontiev, A. I.

doi:10.1007/s10891-010-0404-5

Cited by 26 publications

(6 citation statements)

References 9 publications

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“…The integral flow and heat transfer characteristics are calculated as in [6,7,20,21,[23][24][25][26]. Thus, ζ (the coefficient of hydraulic loss between the two selected successive channel cross sections) is determined from the drop of the total pressure.…”

Section: Specific Features Of the Calculation Methodology: Computatiomentioning

confidence: 99%

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Heat transfer intensification for laminar and turbulent flows in a narrow channel with one-row oval dimples

et al. 2015

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One row dimple reliefs for heat transfer intensification in narrow channels are designed based on the use of oval dimples for laminar and turbulent air flows. A comparative analysis of heat transfer in a channel with 22 one row dimples and a periodic calculation module with one dimple under periodic boundary con ditions at the flow through boundaries is carried out. The focus is made on estimating the thermal and ther mohydraulic effectivenesses of the channels under consideration.

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Section: Specific Features Of the Calculation Methodology: Computatiomentioning

confidence: 99%

“…However, when the insert size is small, it is pref erable to call these dimples based on the spot shape: oval dimples [19]. A significant advantage of isolated oval dimples in comparison with spherical ones with respect to the thermal and thermohydraulic efficiencies was demon strated in [19][20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Heat transfer intensification for laminar and turbulent flows in a narrow channel with one-row oval dimples

et al. 2015

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“…The best known, depending suggested Webb [9] and included in the well-known reference book Sekulic and Shah [10]. These recommendations are as follows (3) For the number of tube rows N from 1 to 3, the j factor is lower and is given by: (4) Note that the authors use the heat from the dependence on the number of rooms, similar to those used in the recommendations [19] for bundles of finned tubes. We have already mentioned that such an attempt is made to the processing of the experimental data obtained in CKTI, it was unsuccessful.…”

Section: Some Data On Plate-and-tube Heat Exchangers Thermal Charactementioning

confidence: 99%

“…Such a situation may for example occur when the steam is overheated by convection or condensation medium with higher temperature or convective cooling gaseous fluid. In order to describe more specifically the positive features of the proposed approach to the heat exchanger efficiency improvement, we use primarily a unique experimental material to study the flat dimpled channels obtained in [17][18][19]. It allows to perform rather convincing preliminary evaluations of the PTHE effectiveness with continuous dimpled fins for which we use the abbreviation PTHED.…”

Section: Several Specific Considerations For Proposed Direction Of Womentioning

confidence: 99%

Ways of dimpling use for efficiency improvement of shell and tube heat exchangers with finned tubes

Gotovsky¹,

Kolpakov²,

Mikhailov³

et al. 2017

IJHT

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To date, accumulated large amount of experimental and theoretical data on the thermal hydraulics dimpled surfaces that demonstrate their high efficiency. However, the extent of the use of these surfaces in the industry far below their potential. This paper discusses the idea of using these surfaces to increase the efficiency of heat exchangers with a high coefficient of fins (e.g., air coolers). This makes it possible to achieve good results with minimal pressure loss increase and admit to widen practical use of such artificial roughness. Importantly, these reliefs provide heat transfer enhancement both on the side with dimples and on the side with protrusions. Most practically suitable for industrial implementation are tube-and-plate heat exchangers with continuous fins and new type of finned tubes − flat-oval tubes with partial finning. When using plane fins with dimples we can substantially increase efficiency if heat transfer intensity on shell side is not high. So we can bring the level of compactness of shell-and-tube heat exchangers up to values characteristic for the plate heat exchangers. Results of calculations showed a possibility of efficiency increase due to dimples to 60-70%.

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“…In [44,45], it was validated on problems of supersonic axisymmetric fl ow around a tear-shaped body with a tapered fl are and past a cylinder with a protruding disk (Mikhalevaeroballistic experiments at the A. F. Ioffe Physical and Technical Institute). The constants C c = 0.02 was validated by comparing results of numerical modeling and experiments on convective heat transfer in a narrow channel with a spherical dimple [46] (Terekhov experiment at the Institute of Thermal Physics of the Siberian Branch of the Russian Academy of Sciences) and with a packet of dimples [47] (Gotovskii experiment at the Central Boiler and Turbine Institute) and in the case of fl ow past a model of a high-rise building [48] (Guvernyuk experiment at the Scientifi c-Research Institute of Mechanics of Moscow State University).…”

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Correction of the Shear-Stress-Transfer Model with Account of the Curvature of Streamlines in Calculating Separated Flows of an Incompressible Viscous Fluid

Исаев

Baranov²,

Zhukova

et al. 2014

J Eng Phys Thermophy

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The necessity of correcting differential semiempirical turbulence models to calculate circulating fl ows of an incompressible viscous fl uid is discussed. Approaches to taking account of the infl uence of the curvature of streamlines on turbulence characteristics arereviewed. Experience gained in modeling numerically twodimensional separated fl ows in a square and a cylindrical cavity on the wall of a plane-parallel channel is analyzed; an additional semiempirical constant in the expression for vortex viscosity of a modifi ed shear-stress-transfer model is substantiated.Introduction. The signifi cant difference in results of numerical modeling of circulating fl ow in the circular cavity on the wall of a rotating channel [1] from the corresponding data obtained with the Doppler laser velocimeter on the experimental setup in Southampton [2] increasingly draws attention to the idea of correction of semiempirical turbulence models used to close Reynolds-averaged Navier-Stokes equations [3] with account of the infl uence of the streamline curvature.In this connection, the present work seeks to analyze experience gained in modeling numerically separated fl ows with turbulence models, in particular, with the frequently used semiempirical turbulence model, i.e., the Mentershear-stresstransfer k-ω model (MSST) in the versions of the year 1993 (MSST1993) and of the year 2003 (MSST2003) [4, 5]. Also, the present work seeks to substantiate the semiempirical constant in the expression for vortex viscosity in the MSST 2003 version [5] using, as examples, the calculations of experimental analogs of separated fl ows of an incompressible viscous medium in a square and a cylindrical cavity on the wall of a plane-parallel channel.Historical Review of Investigations into the Correction of Semiempirical Turbulence Models with Account of the Infl uence of the Streamline Curvature. It is common knowledge that semiempirical models of closure of Reynoldsaveraged Navier-Stokes equations [3, 6] have been constructed for calculation of wall fl ows. In any event, calibration of the constants for them is based on measurements that have been performed on special test beds for model fl ows [7]. Turbulence models are not universal. Thus, the turbulent Prandtl number for the boundary layer is equal to 0.9, and for the jet fl ow, to 0.6 [8]. At the same time, in intricate wall fl ow, one cannot, in practice, single out jet fl ows and, in modeling them using package technologies, takes the turbulent Prandtl number as constant and equal to 0.9 [9]. Also, it should be noted that algebraic turbulent models for calculation of fl ows in curvilinear channels include curvature corrections in expressions for a turbulence scale [3]. Rotation corrections seem even more signifi cant as far as their infl uence, primarily, on velocity profi les is concerned [10].

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Problems of simulating tornado-like heat transfer in turbulent flow past a dimpled relief on a narrow channel wall

Cited by 26 publications

References 9 publications

Heat transfer intensification for laminar and turbulent flows in a narrow channel with one-row oval dimples

Heat transfer intensification for laminar and turbulent flows in a narrow channel with one-row oval dimples

Ways of dimpling use for efficiency improvement of shell and tube heat exchangers with finned tubes

Correction of the Shear-Stress-Transfer Model with Account of the Curvature of Streamlines in Calculating Separated Flows of an Incompressible Viscous Fluid

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