Wall Jet Region Research Articles

Performance analysis of different turbulence models in impinging jet cooling

The characteristics of heat transfer from a hot wall surface for the oblique impingement of a free turbulent slot jet have been investigated numerically. Different turbulent models — the [Formula: see text]-[Formula: see text], [Formula: see text]-[Formula: see text], SST [Formula: see text]-[Formula: see text], cubic [Formula: see text]-[Formula: see text] and quadratic [Formula: see text]-[Formula: see text] models — are used for the prediction of heat transfer and their results were compared with experimental results reported in the literature. The comparison shows that the [Formula: see text]-[Formula: see text], quadratic [Formula: see text]-[Formula: see text] and SST [Formula: see text]-[Formula: see text] models give more unsatisfactory results for the investigated configuration, while the cubic [Formula: see text]-[Formula: see text] model is capable of predicting the local Nusselt number in wall-jet region only. The [Formula: see text]-[Formula: see text] model exhibits the best agreement with the experimental results in both stagnation and wall-jet regions. Further, the [Formula: see text]-[Formula: see text] model is applied to analyze the obliquely impinging jet heat transfer problem. The parametric effects of the jet inclination ([Formula: see text], [Formula: see text] and [Formula: see text]), jet-to-surface distance ([Formula: see text], 6 and 8), Reynolds number ([Formula: see text], 15[Formula: see text]000 and 20[Formula: see text]000), and turbulent intensity ([Formula: see text], [Formula: see text] and [Formula: see text]) have been presented. The heat transfer on the upward direction is seen to decrease, while that on the downward direction it rises for the increasing angle. It is to be noted that as the value of [Formula: see text] decreases, the point of maximum Nusselt number ([Formula: see text]) displaces toward the upward direction from the geometric center point as well as its value reduces. The shifting of the [Formula: see text] is found to be independent of Re and [Formula: see text] within the range considered for the study.

Numerical Simulation of Swirling Impinging Jet Issuing from a Threaded Hole under Inclined Condition.

There are some inclined jet holes in the cooling structure of the leading edge region of gas turbine blades. In order to improve the cooling effect of traditional round holes, this paper proposes to replace the round holes with threaded holes, and studies the complex flow and heat transfer performance of the swirling impinging jet (SIJ) issuing from the 45° threaded holes in the inclined condition by numerical simulation. The influencing factors include jet inclination angle α (45°–90°), jet-to-plate distance (H/d = 2, 4, 6), and Reynolds number (6000–24,000). The results show that the inclination angle and jet-to-plate distance have a great influence on the size, shape, and position of vortices in the jet space, while the Reynolds number has little effect on the vortices. In the inclined state, the impinging cooling effect of the swirling impinging jet is better than that of the circular impinging jet (CIJ), both heat transfer coefficients will degrade significantly when the inclination angle is 45°. When the inclination angle is greater than 45°, compared with the round hole, the enhanced heat transfer region for the swirling jet is in the region of r/d < 3, while both of the Nusselt numbers in the wall jet region are weak, with a value of just 20. At the same time, with the increasing of the inclination angle (α > 45°), the average Nusselt number on target surface holds a constant value. Under the inclined conditions, the heat transfer coefficient on the target surface for the swirling jet is increased totally with the increasing of the Re, but when the Re is larger than 18,000, the rate of enhanced heat transfer gradually weakens.

Wall jet similarity of impinging planar underexpanded jets

Velocity profiles and wall shear stress values in the wall jet region of planar underexpanded impinging jets are parameterized based on nozzle parameters (stand-off height, jet hydraulic diameter, and nozzle pressure ratio). Computational fluid dynamics is used to calculate the velocity fields of impinging jets with height-to-diameter ratios in the range of 15–30 and nozzle pressure ratio in the range of 1.2–3.0. The wall jet has an incomplete self-similar profile with a typical triple-layer structure as in traditional wall jets. The effects of compressibility are found to be insignificant for wall jets with Ma < 0.8. Wall jet analysis yielded power-law relationships with source dependent coefficients describing maximum velocity, friction velocity, and wall distances for maximum and half-maximum velocities. Source dependency is determined using the conjugate gradient method. These power-law relationships can be used for mapping wall shear stress as a function of nozzle parameters.

Impact characteristics and stagnation formation on a solid surface by a supersonic abrasive waterjet

A computational fluid dynamics (CFD) study of the impact characteristics and stagnation formation on a solid target surface by an abrasive waterjet at supersonic velocities is presented to understand the impact process. A CFD model is developed and verified by experimental water and particle velocities and then used to simulate the jet impact process. The trends of the stagnation formation and its effect on the jet flow with respect to the jetting and impacting parameters are amply discussed. It is found that stagnation formation at the impact site increases with an increase in the impact time, nozzle standoff distance and nozzle diameter, while the initial peak velocity at the nozzle exit has little effect on the size of the stagnation zone. It is shown that stagnation markedly changes the water and particle flow direction, so that the particle impact angle is varied and the jet impact area is enlarged. The jet structure may be classified to have a free jet flow region, a jet deflection region with a stagnation zone and a wall jet region. Furthermore, the stagnation affects significantly the waterjet and particle energy transferred to the target surface. The average particle velocity across the jet is reduced by approximately one third due to the damping effect of the stagnation under the conditions considered in this study.

Transient heat transfer characteristics of swirling and non-swirling turbulent impinging jets

A multitude of research has already been undertaken to examine the effects of imparting swirl (S), Reynolds number (Re), and nozzle-to-plate distance (H/D) on the steady-state heat transfer characteristics of turbulent impinging jets. However, no studies to date have compared the transient development of such jets in both swirling and non-swirling conditions. The current paper addresses this gap by using highly resolved (time series) imaged (infrared) data in conditions spanning Re = 11,600, 24,600, and 35,000. The experiments are based on an electrically heated foil (0.025 mm) with jets over S = 0–1.05 and nozzle-to-plate-distances of H/D = 2, 4, and 6.For non-swirling impinging jets, at greater Reynolds numbers, the location of the highest Nusselt number remains fixed for all the time steps in contrast to jets with low Reynolds number. The transient characteristics for H/D = 4 are distinct compared to H/D = 2 and 6, with impingement heat transfer taking more time to reach steady-state for H/D = 4. It is also seen that heat transfer distribution over the impingement plate changes significantly over the small interval of time. For swirling jets, the impingement plate heat transfer characteristics develop simultaneously for the stagnation and wall jet region. The peak Nusselt number shifts to the wall jet region as the intensity of swirl increases. Two correlations (first for non-swirl and low-swirl, later for moderate to high swirl) are proposed to predict the time needed to reach steady-state for Re = 35,000.

Cooling of an isothermal surface having a cavity component by using CuO-water nano-jet

PurposeThe purpose of this study is to numerically analyze the convective heat transfer features for cooling of an isothermal surface with a cavity-like portion by using CuO-water nano jet. Jet impingement cooling of curved surfaces plays an important role in practical applications. As compared to flat surfaces, fluid flow and convective heat transfer features with jet impingement cooling of a curved surface becomes more complex with additional formation of the vortices and their interaction in the jet wall region. As flow separation and reattachment may appear in a wide range of thermal engineering applications such as electronic cooling, combustors and solar power, jet impingement cooling of a surface which has a geometry with potential separation regions is important from the practical point of view.Design/methodology/approachNumerical simulations were performed with a finite volume-based solver. The study was performed for various values of the Reynolds number (between 100 and 400), length of the cavity (between 5 w and 40 w), height of the cavity (between w and 5w) and solid nano-particle volume fraction (between 0 and 4 per cent). Artificial neural network modeling was used to obtain a correlation for the average Nusselt number, which can be used to obtain fast and accurate predictions.FindingsIt was observed that cavity geometrical parameters of the cooling surface can be adjusted to change the flow field and convective heat transfer features. When the cavity length is low, significant contribution of the inclined wall of the cavity on the average Nusselt number is achieved. As the cavity length and height increase, the average Nusselt number, respectively, reduce and slightly enhance. At the highest value of cavity height, significant changes in the convective flow features are obtained. By using nanofluids instead of water, enhancement of average heat transfer in the range of 35-46 per cent is obtained at the highest particle volume fraction.Originality/valueIn this study, jet impingement cooling of an isothermal surface which has a cavity-like portion was considered with nanofluids. Addition of this portion to the impingement surface has the potential to produce additional vortices which affects the fluid flow and convective features in the jet impingement heat transfer. This geometry has the forward-facing step for the wall jet region with flow separation reattachment in the region. Based on the above literature survey and to the best of the authors’ knowledge, jet impingement cooling for such a geometry has never been reported in the literature despite its importance in practical thermal engineering applications. The results of this study may be useful for design and optimization of such systems and to obtain best performance in terms of fluid flow and heat transfer characteristics.

Nozzle exit conditions and the heat transfer in non-swirling and weakly swirling turbulent impinging jets

Investigations have been conducted into turbulent impinging jets but the exact flow dynamics and mechanisms leading to the observed heat transfer distributions at the impingement plane remain outstanding. In particular, use of different swirl generators (vanes, twisted inserts) means the role of varying inflow conditions (at the nozzle exit plane x/D = 0) should be studied to resolve its role on the observed convective heat transfer trends. The present paper studies axisymmetric turbulent weakly swirling (S = 0.31) jets (D = 40 mm) impinging onto a heated plate. Parameters varied include inflow conditions and the effects of impingement distance (H/D = 2, 4, and 6). The Reynolds Averaged Navier Stokes (RANS) equations are used to model the jets using the k-kl-ω turbulence model, which is benchmarked against other models. Three azimuthal ( ) velocity profiles at a Reynolds (Re) number of 24,600 are used at the nozzle exit plane: Uniform (UP), Solid Body Rotation (SBR), and Parabolic Profiles (PP). The start of the wall jet region, designated through elevated levels of turbulent kinetic energy correlates well with the widely observed first peak in Nu distribution. This is however extremely sensitive to the imposition of any swirl, with the application of even weak swirl (S = 0.31) minimally modifying flow dynamics (in the upstream jet region) and leading to recirculation zones stabilized at the impingement plane. This occurs in near-field impingement (H/D) for some inflow conditions (S031-UP), but not others thereby highlighting the significance varied nozzle and swirl generation methods on trends observed in the literature. The imposition of elevated levels of turbulence at the nozzle inflow (x/D = 0) appreciably modifies the heat transfer distribution, particularly in far-field impingement (H/D = 6).

Flow and thermal characteristics of jet impingement on a flat plate for small nozzle to plate spacing using LES

This paper presents a study of flow and thermal characteristics of jet impingement heat transfer by large eddy simulation (LES) using the wall adapting local eddy (WALE) viscosity sub-grid scale (SGS) model. OpenFOAM 4.1, a finite-volume based customized open source computational fluid dynamics (CFD) solver, is used for computations. Turbulent slot jet impingement on a solid flat plate for a small nozzle to plate spacing (H/B = 4, where H denotes the gap between jet and plate and B the slot width) and Reynolds number of 20000 is considered. The capability of the WALE SGS model is first evaluated by comparing the results of flow and heat transfer features including turbulence profiles with the reported experimental results and good agreements are observed. A secondary peak in Nusselt number (Nu) profile on the impingement plate is observed in accordance with the reported results. In order to gain a good understanding of flow and heat transfer characteristics, mean and r.m.s. values of velocity and temperature, Nusselt number (Nu), turbulent structures and iso-surfaces of various flow properties were analyzed in detail. Large coherent structures, flow acceleration and an augmentation in turbulence were correlated with the existence of a secondary peak in Nu profile. A detailed discussion on flow and heat transfer characteristics is presented in the vicinity of stagnation, impingement plate and wall jet regions.

Impingement of propeller jet on a vertical quay wall

This study experimentally investigates the mean and turbulent flow fields of a propeller jet impinging on a vertical quay wall. Four impingement distances, namely, wall clearances (= longitudinal distance between the propeller and vertical wall), were used to examine their influence on the flow behaviors. In order to investigate the characteristics of the three-dimensional impinging jet, both the streamwise (jet central plane) and transverse (impingement plane) flow fields were measured for each impingement distance using the particle image velocimetry (PIV) technique. Based on the wall clearance, three regions are identified, namely free, impingement and wall jet regions. Additionally, the results show that the evolution of the impinging jet is governed by two mechanisms: jet diffusion and wall obstruction. Their relative importance under varying wall clearances was interpreted in terms of the mean flow patterns and energy dissipation. Moreover, the proper orthogonal decomposition (POD) method is employed to identify the dominant flow structures associated with these two mechanisms in terms of the POD modes and their corresponding dominant frequency, which in turn provides a quantitative means to single out the individual flow mechanism.

Turbulence energetics in an axisymmetric impinging jet flow

Turbulence energetics is investigated in the impingement and wall jet regions of an axisymmetric impinging jet flow, by using the two-dimensional particle-image velocimetry measurement technique. The inlet-based Reynolds number is equal to 5200, and the height to the diameter ratio is equal to 5.95. This study shows that turbulence kinetic energy balances in outer, middle, and inner layers of the impingement region differ greatly from each other. The balances in near-field and far-field wall jet regions differ, as well. This study also provides various useful insights into the directional characteristics of the energy transports. For example, it has revealed that the turbulence diffusion process transports energy in the upstream direction in the jet core, but obliquely in the mixing layers. The balance terms are decomposed into physically meaningful spatial components, which, among various other insights, show that the negative production rate that is earlier reported in the stagnation region is caused by the negative work contributions of the radial and the tangential Reynolds stresses. This study, overall, lets us have a thorough understanding of the turbulence production, the convection, the turbulence diffusion, and the viscous diffusion processes, while the turbulence dissipation and the pressure diffusion terms are clubbed together and obtained as the residual of the energy balance equation. Information that is extracted from the residual has demonstrated the failure of Lumley’s model to estimate the pressure diffusion rate near the impingement surface.

Investigation of the Boundary Layer Flow Under Engine-Like Conditions Using Particle Image Velocimetry

The turbulent boundary layer flow in internal combustion (IC) engines has a significant effect on the in-cylinder flow and the wall heat transfer. A detailed analysis of the in-cylinder near-wall flow was carried out on an optical steady flow test bench by using high-resolution particle image velocimetry (PIV) in order to characterize the in-cylinder boundary layer flow in this study. The difference between the in-cylinder boundary layer and the canonical turbulent boundary layer was analyzed. The experimental results show that small-scale vortices with a length scale of about 1–2 mm in the instantaneous flow fields appeared in the wall jet region due to the entrainment of the free jet in the outer region of the wall jet. The viscous sublayer thickness decreased from 0.5 mm to 0.3 mm as the valve lift increased from 2.32 mm to 7.975 mm and the pressure drop from 0.5 kPa to 1 kPa. The dimensionless velocity profile is in good agreement with the law of the wall in the viscous sublayer. However, no obvious logarithmic law distribution region was observed in the logarithmic layer. The distribution of the Reynolds stress and the turbulent kinetic energy is similar to that of the canonical turbulent boundary layer. But the Reynolds stress had a much larger magnitude because the turbulent velocity measured in this boundary layer included not only the turbulence generated by wall shear but also the large-scale turbulent vortices caused by the wall jet.

Vortex dynamics in a normally impinging planar jet

The flow development of a jet issued from a high-aspect ratio slot nozzle impinging on a flat plate is investigated experimentally. Time-resolved, two-component particle image velocimetry is used to characterize the flow for Reynolds numbers based on slot width and streamwise jet centerline velocity of 3000 and 6000, and impingement height ratios of 2 and 4. A quantitative description of the vortex dynamics is provided and the effects of Reynolds number and impingement height on the vortex evolution are characterized for the experimental conditions investigated. Primary vortices are shed in a highly periodic manner with strengths that scale with Reynolds number. Primary vortex merging is observed in the wall-jet region for all test conditions while increasing the impingement height ratio from 2 to 4 causes vortex merging to also occur in the free-jet region. Passage of single and merged primary vortices induces the formation of secondary vortices along the impingement surface, though the shedding frequencies of these secondary structures exhibit higher variability than that of the primary vortices. The secondary vortices are similar in strength to the primary vortices for a Reynolds number of 3000, but their relative circulation is decreased at a Reynolds number of 6000. Secondary vortex shedding at the lower Reynolds number leads to a higher growth rate of the wall-jet half-width due to pairing with primary vortices and subsequent ejection away from the surface, which is not found at the higher Reynolds number investigated.

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

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.

Influence of shock structure on heat transfer characteristics in supersonic under-expanded impinging jets

In this study, the relationship between the shock structure of impinging jet flow and target wall heat transfer characteristics was investigated. In the case of a high Reynolds number impinging jet that can enter the supersonic flow regime, the stagnation temperature of the impinged surface is affected by the jet structure as well as other factors, such as the nozzle to plate distance and radial distance. When the jet flow velocity becomes supersonic, shock structures form at the downstream of the nozzle exit. Complicated shock structures, such as the Mach shock disk and plate shock, are expected to affect the heat transfer characteristics of the impingement surface. In this study, the cooling performance of a supersonic nitrogen (N2) jet is investigated by measuring the impinged surface temperature, and the flow of the jet is visualized by schlieren imaging. The visualized image and surface temperature are compared to clarify the shock structure-related heat transfer characteristics. Under experimental conditions where the nozzle pressure ratio changes to a moderate and highly under-expanded regime, the surface temperature fluctuates according to the changes of jet structures in each condition. According to a position of Mach crossing point, which is an intersection of oblique shock structures, a behavior of jet fluid is decided to be trapped inside the recirculation zone or to be spread to wall jet region. In case that the jet fluid is trapped, the cooling performance of the supersonic jet is significantly reduced and vice versa. Therefore, the heat transfer characteristics can be explained by roles of the jet flow field structures including the recirculation flows and shock locations.

Experimental study on single phase operation of microjet augmented heat exchanger with enhanced heat transfer surface

The article presents experimental investigations on a prototype heat exchanger. Presented research is focused on combined active and passive enhancement techniques of surface modification and microjet impingement. The results were compared to reference plate heat exchanger without microjet impingement.The Wilson plot method was applied to determine the heat transfer coefficients in the single phase operation. The heat exchanger was capable of exchanging 300 W of thermal energy at LMTD of 40 K. The obtained overall heat transfer rates reach 600 W/m2.Introducing knurled surface resulted in ∼10% increase heat transfer area, and similar enhancement in transferred heat in reference to plate heat exchanger geometry. Knurled surface decreased heat transfer in combination with a multi-jet impingement in comparison to a smooth surface. A possible explanation of that effect is that the flow in wall jet region is disrupted by the knurled surface and directed in the bulk of the fluid. Initiating mixing with colder fluid, thicker thermal boundary layer, and affecting local temperature distribution.

Flow visualization and mechanisms of three-electrode sliding discharge plasma actuator

The unsteady flow characteristics induced by a three-electrode sliding discharge plasma actuator under different actuation modes were analyzed by ensemble averaged and phase-locked particle image velocimetry. The discharge morphologies, voltage–current waveforms, and particle image velocimetry data in continuous mode were compared to clarify the performance modification mechanism of the pulsed three-electrode sliding discharge. The particle image velocimetry results revealed that deformation of the electromagnetic field around the additional electrode caused by applying a high DC voltage triggers changes in the induced flow field. When the three-electrode sliding discharge plasma actuator is actuated in continuous mode, a strong accelerated wall jet and homogeneous discharge region covering the whole gap between the two exposed electrodes are generated. The large discharge extension mainly results from the accelerated drift of positive ion particles created during the positive half cycle, while negatively ionized particles have a significantly larger impact on the induced velocity production process. In the pulsed mode, when a positive high DC voltage ( VDC = 18 kV) is applied to the additional electrode, both the size and magnitude of the induced vortex structures increase, and highly accelerated regions are periodically generated. When V DC = −18 kV, the induced velocity field evens out, the accelerated region becomes less obvious, the intensity of both the primary and secondary vortices decreases, and the vortex structure dissipates faster, owing to the turbulent motion of ionized particles. An additional positive DC component attracts the negatively ionized particles during the negative half cycle, improving the velocity and intensity of the stream-wise vortices, which is very attractive for flow control applications.

Turbulence characteristics of radially-confined impinging jet flows

Radially confined, axisymmetric impinging jet flows are investigated by using the standard particle image velocimetry experimental technique. The confinement is achieved by placing a confinement block around a jet, co-axially. The inner diameter of the block is successively varied to nine different values. The inlet-based Reynolds number of the jet is kept constant at 5000. The nine diametric values yielded nine different flows of widely different characteristics. Among other usage, an insight into the flow characteristics can be helpful in designing compact impinging jet applications, as such a radially confined flow is equivalent to passing the pre-impingement jet through a hole perforated in a solid wall (i.e. the jet source can be placed behind a wall). The study has revealed that the flows, in general, form two circulation zones, three mixing layers, and two boundary layers. Based on turbulence characteristics of the five shear layers, overall characteristics of the flows are understood systematically. Mean velocity and various turbulence statistics are also presented, and mechanisms underlying behind their variations are explained. Finally, scaling laws are obtained for the mean velocity and for the turbulence statistics, both in the impingement and in the wall jet regions.

Relaminarization of a hot air impingement on a flat plate

The research mainly focuses on a numerical analysis for heat transfer in the transition flow regimes. The simulation is presented by using ANSYS-FLUENT and Reynolds Averaged Navier Stokes (RANS) technique is employed in order to simulate the complex flow fields. The turbulent jet which impinges on the flat plate with a constant surface heat fluxes is tested. The average Nusselt number predictions are also calculate and compared with existing measurement results. The jet Reynolds number is set to 23,000 which based on jet nozzle diameter, while a jet-toplate spacing of H/D is fixed at 2.0. The turbulence models evaluated in the present study are one equation Spalart Allmaras (SA) model, k-ɛ, shear stress transport (SST) k-ω and SST with transition model. It can be summarized that the SA, k-ɛ, and SST k-ω models fail to calculate the global trend of the instantaneous simulated Nusselt number profiles. Only the simulated results from the SST with transition model provides agree fairly well with experimental results. Moreover, the first highest point of predicted Nusselt number are close to the stagnation point and decrease monotonically in the radial direction within the wall jet region. The second peak of Nusselt number prediction is also observed, and the RANS simulations can capture the relaminarization mechanisms within the boundary layer near walls.

Impinging jets array: an experimental investigation and numerical modeling

This paper reports on the measurements of wall shear stress and static pressure along a smooth static wall upon which jet impingement occurs. The effect of a single circular jet, respectively an array of jets is studied using a high speed/resolution camera. The areas of interest are the stagnation region and the wall jet region, where the jet is deflected from axial to radial direction. The effect of increasing the distance between the inlets is also investigated. The results are obtained by performing direct flow experimental visualizations and CFD numerical simulations, using the Reynolds averaged Navier-Stokes (RANS) approach with the commercial software ANSYS Fluent. The findings suggest that the smaller the nozzle-to-wall distance is, the higher the pressure peak. The wall shear stress has a bimodal distribution; at stagnation point, the wall shear stress is 0. An increase in the number of inlets produces the effect of a decrease in the stagnation point pressure. The greater the inter-inlet distance is, the greater the stagnation point pressure (there is less inter-jet mixing, less energy is lost in vortices formed between jets).

OpenFOAM based LES of slot jet impingement heat transfer at low nozzle to plate spacing using four SGS models

The objective of the present investigation is to assess the effectiveness of large eddy simulation (LES) in turbulent slot jet impingement heat transfer at low nozzle to plate spacing. Four different sub-grid stress (SGS) models, namely, Smagorinsky, WALE (wall adapting local eddy-viscosity), k-equation and dynamic k-equation, were considered for Reynolds number of 20,000. Computations were performed using OpenFOAM, an open source finite-volume based CFD code. Time and span-wise averaged mean streamwise velocity and root mean square (r.m.s.) velocity fluctuations in the stagnation and wall jet regions are presented. Nusselt number distributions on the impingement wall are also presented. The computed LES results are compared with the reported experimental data. A secondary peak in the Nusselt number was observed using the four SGS models as in the experimental data. LES of slot jet impingement heat transfer using four SGS models, including WALE, has been investigated for the first time in the present paper. It is observed that the WALE and dynamic k-equation SGS models perform well in complex flow regions of turbulent slot jet impingement heat transfer.