Flows Generated by the Impingement of a Jet on a Rotating Surface: Part II—Detailed Flow Structure and Analysis

1996 ◽  
Vol 118 (1) ◽  
pp. 68-73 ◽  
Author(s):  
S. Brodersen ◽  
D. E. Metzger ◽  
H. J. S. Fernando
Keyword(s):  
Jet Impingement ◽  
Rotating Disk ◽  
Flow Patterns ◽  
Velocity Fields ◽  
Base Flow ◽  
Basic Flow ◽  
Turbulent Jet ◽  
Rotating Surface ◽  
Interaction Problem ◽  
Impingement Point

In Part I of this investigation, the basic flow patterns resulting from the interaction of a turbulent jet and a rotating disk flow were presented paying particular attention to mean and turbulent velocity fields around the jet impingement point on the disk and the flow patterns above the disk in the absence of the jet. The latter was used as a base flow pattern, on which the influence of the jet impingement could be assessed. In Part II, further details of the jet/disk flow interaction problem are discussed in the context of potential turbomachinery cooling applications and previous experimental results.

Liquid Jet Impingement Cooling of a Rotating Disk

1986 ◽  
Vol 108 (3) ◽  
pp. 540-546 ◽  
Author(s):  
H. J. Carper ◽  
J. J. Saavedra ◽  
T. Suwanprateep
Keyword(s):  
Reynolds Number ◽  
Average Nusselt Number ◽  
Convective Heat Transfer Coefficient ◽  
Jet Impingement ◽  
Rotating Disk ◽  
Liquid Jet ◽  
Flow Rates ◽  
Impingement Cooling ◽  
Angular Velocities ◽  
Jet Nozzle

Results are presented from an experimental study conducted to determine the average convective heat transfer coefficient for the side of a rotating disk, with an approximately uniform surface temperature, cooled by a single liquid jet of oil impinging normal to the surface. Tests were conducted over a range of jet flow rates, jet temperatures, jet radial positions, and disk angular velocities with various combinations of three jet nozzle and disk diameters. Correlations are presented that relate the average Nusselt number to rotational Reynolds number, jet Reynolds number, jet Prandtl number, and dimensionless jet radial position.

Multiple Flow Patterns and Heat Transfer in Confined Jet Impingement

2002 ◽  
Author(s):  
X. Li ◽  
J. L. Gaddis ◽  
T. Wang
Keyword(s):  
Heat Transfer ◽  
Flow Field ◽  
Boundary Conditions ◽  
Jet Impingement ◽  
Flow Patterns ◽  
Computational Results ◽  
Initial Flow ◽  
Flow Parameters ◽  
Visualization Experiment ◽  
Exit Boundary

The flow field of a 2-D laminar confined impinging slot jet is investigated. Numerical results indicate that there exist two different solutions in some range of geometric and flow parameters. The two steady flow patterns are obtained under identical boundary conditions but only with different initial flow fields. Three different exit boundary conditions are investigated to eliminate artificial effects. The different flow patterns are observed to significantly affect the heat transfer. A flow visualization experiment is carried out to verify the computational results and both flow patterns are observed. The bifurcation mechanism is interpreted and discussed.

scholarly journals Dominant Fish and Macroinvertebrate Response to Flow Changes of the Geum River in Korea

Water ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 942 ◽  
Author(s):  
Hyeongsik Kang ◽  
Byungwoong Choi
Keyword(s):  
Flow Patterns ◽  
Base Flow ◽  
Physical Habitat ◽  
Aquatic Species ◽  
Morphology Change ◽  
Suitability Index ◽  
Natural Flow ◽  
Habitat Simulation ◽  
Target Fish ◽  
The Impact

This study presents the impact of natural flow patterns on downstream aquatic species habitats in a reach of the Geum River, Korea. The study reach is a 13.4 km long, located downstream of the Yongdam Dam. To assess such an impact, this study performed physical habitat simulations. The River2D model was used for the computation of the flow field and morphology, and the Habitat Suitability Index (HSI) model for the habitat simulation. Three habitat variables—flow depth, velocity, and substrate were used. The Zacco platypus and Baetis fuscatus were selected as the target fish and benthic macro-invertebrate, respectively. Using the building block approach (BBA), the scenarios for modifying dam operations were constructed in the study reach. Scenario 1, scenario 2, and scenario 3 were proposed by using the magnitude–duration concept, base flow allocation concept, and seasonally adjusted minimum flow allocation concept, respectively. Simulation results indicated that the scenarios’ effects significantly increased by about 14.3% for the weighted usable area (WUA). In addition, the morphology change with the restoration of flood events was investigated. It was revealed that the morphology change in the physical habitat simulations further increased by about 13% for the WUA. The change of dam operations through natural flow patterns is more advantageous to aquatic species.

Jet Cooling at the Rim of a Rotating Disk

1979 ◽  
Vol 101 (1) ◽  
pp. 68-72 ◽  
Author(s):  
D. E. Metzger ◽  
W. J. Mathis ◽  
L. D. Grochowsky
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Jet Impingement ◽  
Rotating Disk ◽  
Impinging Jets ◽  
Turbine Engine ◽  
Transfer Rates ◽  
Jet Cooling ◽  
Geometric Conditions ◽  
Face Contour

Results are presented from an experimental study conducted to measure heat transfer rates at the rim of a rotating disk convectively cooled by impinging jets. The disk face contour radially inward from the rim is varied to simulate the geometric conditions found on gas turbine engine rotors. Heat transfer rates are found to be relatively unaffected by impingement for jet flowrates less than the order of one-tenth the disk pumping flow. Disk pumping flows are evaluated through the use of an analysis which accounts for the presence of the disk hub. At larger jet flowrates, heat transfer rates increase strongly with increasing jet flow, reaching two to three times the no-impingement values at jet flowrates approximately equal to the pumped flow. All the heat transfer results, both with and without jet impingement, are essentially unaffected by changes in the disk face contour.

Computational investigation of turbulent jet impinging onto rotating disk

2007 ◽  
Vol 17 (3) ◽  
pp. 284-301 ◽  
Author(s):  
A.C. Benim ◽  
K. Ozkan ◽  
M. Cagan ◽  
D. Gunes
Keyword(s):  
Boundary Conditions ◽  
Isotropic Turbulence ◽  
Domain Size ◽  
Rotating Disk ◽  
Turbulent Jet ◽  
Turbulence Structure ◽  
Computational Domain ◽  
Convergence Criteria ◽  
Computational Investigation ◽  
Content Type

PurposeThe main purpose of the paper is the validation of a broad range of RANS turbulence models, for the prediction of flow and heat transfer, for a broad range of boundary conditions and geometrical configurations, for this class of problems.Design/methodology/approachTwo‐ and three‐dimensional computations are performed using a general‐purpose CFD code based on a finite volume method and a pressure‐correction formulation. Special attention is paid to achieve a high numerical accuracy by applying second order discretization schemes and stringent convergence criteria, as well as performing sensitivity studies with respect to the grid resolution, computational domain size and boundary conditions. Results are assessed by comparing the predictions with the measurements available in the literature.FindingsA rather unsatisfactory performance of the Reynolds stress model is observed, in general, although the contrary has been expected in this rotating flow, exhibiting a predominantly non‐isotropic turbulence structure. The best overall agreement with the experiments is obtained by the k‐ω model, where the SST model is also observed to provide a quite good performance, which is close to that of the k‐ω model, for most of the investigated cases.Originality/valueTo date, computational investigation of turbulent jet impinging on to “rotating” disk has not received much attention. To the best of the authors' knowledge, a thorough numerical analysis of the generic problem comparable with present study has not yet been attempted.

An experimental and simulation study of the flow pattern characteristics of water jet impingements in boreholes

2021 ◽  
pp. 014459872110520
Author(s):  
Yabin Gao ◽  
Xin Xiang ◽  
Ziwen Li ◽  
Xiaoya Guo ◽  
Peizhuang Han
Keyword(s):  
High Speed ◽  
Impact Force ◽  
Jet Impingement ◽  
Flow Patterns ◽  
Water Jet ◽  
Solid Boundary ◽  
Force Model ◽  
Water Jets ◽  
Contact Surfaces ◽  
The Impact

Hydraulic slotting has become one of the most common technologies adopted to increase permeability in low permeability in coal field seams. There are many factors affecting the rock breaking effects of water jets, among which the impact force cannot be ignored. To study the influencing effects of contact surface shapes on jet flow patterns and impact force, this study carried out experiments involving water jet impingement planes and boreholes under different pressure conditions. The investigations included numerical simulations under solid boundary based on gas–liquid coupling models and indoor experiments under high-speed camera observations. The results indicated that when the water jets impinged on different contact surfaces, obvious reflection flow occurred, and the axial velocity had changed through three stages during the development process. Moreover, the shapes of the contact surfaces, along with the outlet pressure, were found to have impacts on the angles and velocities of the reflected flow. The relevant empirical formulas were summarized according to this study's simulation results. In addition, the flow patterns and shapes of the contact surfaces were observed to have influencing effects on the impact force. An impact force model was established in this study based on the empirical formula, and the model was verified using both the simulation and experimental results. It was confirmed that the proposed model could provide important references for the optimization of the technical parameters water jet systems, which could provide theoretical support for the further intelligent and efficient transformation of coal mine drilling water jet technology.

Numerical study of an axisymmetric turbulent jet-impingement flow

1993 ◽  
Author(s):  
YEU-PIN YEH ◽  
F. CHEUNG ◽  
KENNETH KUO ◽  
THOMAS LITZINGER
Keyword(s):  
Numerical Study ◽  
Jet Impingement ◽  
Turbulent Jet

scholarly journals Heat transfer during pulsating liquid jet impingement onto a vertical wall

2020 ◽  
Author(s):  
J. Wassenberg ◽  
P. Stephan ◽  
T. Gambaryan-Roisman
Keyword(s):  
Heat Transfer ◽  
Vertical Wall ◽  
Jet Impingement ◽  
High Heat ◽  
Heated Wall ◽  
Liquid Jet ◽  
Pulsation Frequency ◽  
Cooling Efficiency ◽  
Heat Transfer Efficiency ◽  
Impingement Point

Abstract Liquid jet impingement is used for cooling and cleaning in various industrial branches. The advantages of jet impingement include high heat and mass transport rates in the vicinity of the impingement point. Pulsating liquid jets impinging on horizontal substrates with a pulsation frequency around 100 Hz have been shown to increase the cooling efficiency in comparison to jets with continuous mass flow rates. The influence of jet pulsation on cooling efficiency for impingement of horizontal jets onto vertical walls has not yet been investigated. In the case of a vertical heated wall, gravity contributes to the liquid flow pattern. In particular, if the time span between two pulses is sufficiently long, the liquid drainage from the region above the impingement point can contribute to heat transport without increasing the average flow rate of the cooling medium. In this work, the influence of pulsations on heat transfer during impingement of a horizontal liquid jet onto a vertical wall is investigated experimentally for the pulsation frequency range 1–5 Hz. The results regarding increase of heat transfer efficiency are related to flow patterns developing by impingement of successive pulses, as well as to the liquid splattering.

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