Performance enhancement of an impinging jet system using different working fluids-A numerical study

The present comparative numerical study is between V-shape protruded, dimple textured, and untextured bearing. The performance parameters in terms of the load-carrying capacity and coefficient of friction are computed by solving governing Reynold’s equation of the lubricant fluid flow. The governing equation is solved by the finite element method by assuming that the fluid is Newtonian and isoviscous in nature. The effect of eccentricity ratios, texture distribution, texture heights, and texture depths are considered for the analysis in both textured bearings. From simulated results, the load-carrying capacity and coefficient of friction is found to be maximum for protruded textured bearing in full textured region and first half-textured region respectively as compared to untextured bearings. Finally, optimal operating and geometrical parameters of textured bearing is obtained by computing performance enhancement ratio, which is the ratio of the load-carrying capacity to the coefficient of friction. The maximum value of the performance enhancement ratio is found for protruded and dimple textured bearing in full texturing and second half-region corresponding to the eccentricity ratio of 0.8 and 0.6 respectively at texture height and depth of 0.4.

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Thermal performance enhancement in a wedge duct with in-line pin fins combined with vortex generators

International Journal of Numerical Methods for Heat &amp Fluid Flow ◽

10.1108/hff-08-2018-0455 ◽

2019 ◽

Vol 29 (8) ◽

pp. 2545-2565

Author(s):

Safeer Hussain ◽

Jian Liu ◽

Lei Wang ◽

Bengt Ake Sunden

Keyword(s):

Heat Transfer ◽

Boundary Layer ◽

Thermal Performance ◽

Performance Enhancement ◽

Numerical Study ◽

Vortex Generators ◽

Content Type ◽

Pin Fin ◽

Pin Fins ◽

Cooling Enhancement

Purpose The purpose of this paper is to enhance the heat transfer and thermal performance in the trailing edge region of the vane with vortex generators (VGs). Design/methodology/approach This numerical study presents the enhancement of thermal performance in the trailing part of a gas turbine blade. In the trailing part, generally, pin fins are used either in staggered or in-line arrangements to enhance the heat transfer. In this study, based on the idea from heat exchangers, pin fins are combined with VGs. A pair of VGs is embedded in the boundary layer upstream of each pin fin in the first row of the pin fin array having an in-line configuration. The effects of the VG angle relative to the streamwise direction and streamwise distance between the pin fin and VGs are investigated at various Reynolds numbers. Findings The results indicated that the endwall heat transfer is enhanced with the addition of VGs and the heat transfer from the surfaces of the pin fins. The level of heat transfer enhancement compared to the case without VGs is more significant at high Reynolds number. The surfaces of the VGs also show a significant amount of heat transfer. Study of the angle of the attack suggested that a high angle of attack is more appropriate for pin fin cooling enhancement whereas an intermediate gap between the VGs and pin fins shows considerable improvement of thermal performance compared to the small and large gaps. The phenomenon of heat transfer augmentation with the VGs is demonstrated by the flow field. It shows that the enhancement of heat transfer is governed by the mixing of the flow as a result of the interaction of vortices generated by the VGs and pin fins. Originality/value VGs are used to disturb the thermal boundary layer. It shows that heat transfer is augmented as a result of the interaction of vortices associated with VGs and pin fins.

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Numerical study of an impinging jet in cross-flow within and without influence of vortex generator structures on heat transfer

Heat and Mass Transfer ◽

10.1007/s00231-019-02728-5 ◽

2019 ◽

Vol 56 (3) ◽

pp. 797-810

Author(s):

Ardalan Javadi

Keyword(s):

Heat Transfer ◽

Numerical Study ◽

Cross Flow ◽

Vortex Generator ◽

Impinging Jet ◽

Jet In Cross Flow

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Numerical study of the heat and momentum transfer between a flat plate and an impinging jet of power law fluids

International Journal of Heat and Mass Transfer ◽

10.1016/j.ijheatmasstransfer.2019.06.072 ◽

2019 ◽

Vol 141 ◽

pp. 102-111 ◽

Cited By ~ 2

Author(s):

J. Ortega-Casanova ◽

M. Jimenez-Canet ◽

F.J. Galindo-Rosales

Keyword(s):

Flat Plate ◽

Momentum Transfer ◽

Power Law ◽

Numerical Study ◽

Impinging Jet ◽

Power Law Fluids ◽

Heat And Momentum Transfer

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Numerical study of melting performance enhancement for PCM in an annular enclosure with internal-external fins and metal foams

International Journal of Heat and Mass Transfer ◽

10.1016/j.ijheatmasstransfer.2020.119348 ◽

2020 ◽

Vol 150 ◽

pp. 119348 ◽

Cited By ~ 10

Author(s):

Chunrong Zhao ◽

Michael Opolot ◽

Ming Liu ◽

Frank Bruno ◽

Simone Mancin ◽

...

Keyword(s):

Performance Enhancement ◽

Numerical Study ◽

Metal Foams

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Investigation of the Flow Structures in Supersonic Free and Impinging Jet Flows

Journal of Fluids Engineering ◽

10.1115/1.4023190 ◽

2013 ◽

Vol 135 (3) ◽

Cited By ~ 18

Author(s):

C. Chin ◽

M. Li ◽

C. Harkin ◽

T. Rochwerger ◽

L. Chan ◽

...

Keyword(s):

High Speed ◽

Numerical Study ◽

Experimental Studies ◽

Turbulence Models ◽

Impinging Jet ◽

Optical Methods ◽

Navier Stokes ◽

Jet Flows ◽

Shock Cell ◽

Rans Turbulence Models

A numerical study of compressible jet flows is carried out using Reynolds averaged Navier–Stokes (RANS) turbulence models such as k-ɛ and k-ω-SST. An experimental investigation is performed concurrently using high-speed optical methods such as Schlieren photography and shadowgraphy. Numerical and experimental studies are carried out for the compressible impinging at various impinging angles and nozzle-to-wall distances. The results from both investigations converge remarkably well and agree with experimental data from the open literature. From the flow visualizations of the velocity fields, the RANS simulations accurately model the shock structures within the core jet region. The first shock cell is found to be constraint due to the interaction with the bow-shock structure for nozzle-to-wall distance less than 1.5 nozzle diameter. The results from the current study show that the RANS models utilized are suitable to simulate compressible free jets and impinging jet flows with varying impinging angles.

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