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Saturday, May 2, 2020 | History

1 edition of Jet array impingement flow distributions and heat transfer characteristics found in the catalog.

Jet array impingement flow distributions and heat transfer characteristics

Jet array impingement flow distributions and heat transfer characteristics

effects of initial crossflow and nonuniform array geometry

by

  • 296 Want to read
  • 21 Currently reading

Published by National Aeronautics and Space Administration, Scientific and Technical Information Branch, For sale by the National Technical Information Service] in Washington, D.C, [Springfield, Va .
Written in English

    Subjects:
  • Heat -- Transmission.,
  • Jets -- Fluid dynamics.

  • Edition Notes

    StatementL.W. Florschuetz ... [et al.] ; prepared for Lewis Research Center.
    SeriesNASA contractor report -- 3630., NASA contractor report -- NASA CR-3630.
    ContributionsFlorschuetz, L. W., Lewis Research Center., United States. National Aeronautics and Space Administration. Scientific and Technical Information Branch.
    The Physical Object
    Paginationvii, 170 p. :
    Number of Pages170
    ID Numbers
    Open LibraryOL15266155M

      We experimentally investigated the effects of both the compressibility and nozzle width on the local heat transfer distribution of microscale unconfmed slot jets impinging on a uniformly heated flat plate. We made heat transfer measurements under the following experimental conditions; Reynolds numbers of Re = ~, Mach numbers of Ma = Author: Seung-Ho Han, Hyun-Jin Park, Dae-Hee Lee. transfer is enhanced. For any impingement jet array situations, cross flow is inevitable. Some studies have shown how cross flow affects heat transfer. These studies presented correlations that account for regular arrays of impingement jet holes with low to moderate cross flow effect. Both correlations show moncotonous decreases in Nusselt Cited by: Get this from a library! Jet array impingement with crossflow - correlation of streamwise resolved flow and heat transfer distributions. [L W Florschuetz; Darryl E Metzger; C R Truman; United States. National Aeronautics and Space Administration. Scientific and Technical Information Branch.; Lewis Research Center.; Arizona State University.]. Liquid Jet Impingement Cooling. Liquid jets are often used to cool surfaces because the efficiency is high, and the hardware is simple. These studies aimed to develop a basis for controlled engineering application of such jets. Both experimental and analytical studies have been conducted, leading to relatively complete expressions for the radial distribution of the .

      Free Online Library: Experimental investigation of jet impingement cooling using square ribbed target surface.(Report) by "Advances in Natural and Applied Sciences"; Science and technology, general Combustion chambers Analysis Cooling Heat transfer Jets Jets (Fluid dynamics) Turbine blades Mechanical properties Thermal properties Turbines Blades.


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Jet array impingement flow distributions and heat transfer characteristics Download PDF EPUB FB2

Tion of flow distributions and heat transfer characteristics for two-dimen­ sional arrays of circular air jets impinging on a surface parallel to the jet orifice plate. The configurations considered were intended to model those of interest in current and contemplated gas turbine airfoil midchord cooling applications.

Jet array impingement flow distributions and heat transfer characteristics: effects of initial crossflow and nonuniform array geometry. superficial jet mass flux based on jet plate or impingement area regional average heat transfer coefficient defined in terms of overall array parameters, Eqs.

() and () mean value of h over entire array impingement region regional average heat transfer coefficient defined in terms ofFile Size: 4MB. Two-dimensional arrays of circular air jets impinging on a heat transfer surface parallel to the jet orifice plate are considered.

The jet flow, after impingement, is constrained to exit in a single direction along the channel formed by the jet orifice plate and the heat transfer surface. Two-dimensional arrays of circular jets of air impinging on a heat transfer surface parallel to the jet orifice plate are considered.

The air, after impingement, is constrained to exit in a single direction along the channel formed by the surface and the jet by: The fluid flow and heat transfer characteristics of an impinging jet with a combined active–passive device were investigated.

The combined device consisted of triangular tabs and a synthetic jet array that provided periodic disturbance to the jet’s shear by: 6. Jet impingement on a rib. fitted target sur face disrupts the wall jet and thus level of.

turbulence and heat transfer are expected to increase [20]. Katti and Prab hu. researchers have studied the forced convection heat transfer from jet arrays. This review paper gives various experimental and numerical approaches on jet impingement heat transfer process.

In the course of the review, the flow and heat transfer characteristics of multiple impinging jets are introduced. Finally, the heat transfer characteristics in terms of the Nusselt number is presented. Flow field characteristics The proper prediction of the heat transfer values needs an analysis of the flow field mechanism.

An array of presented six nozzles has a very complex behavior. Firstly, it is a result of the deflection at the stagnation by: 8. bulence. The efiects of these vortical °ow structures on the heat transfer characteristics in an impinging jet °ow are also presented.

Speciflc stages of the vortex development are shown to enhance vertical °uctuations and hence increase heat transfer to the jet °ow, resulting in secondary peaks in the radial distribution.

Two-dimensional arrays of circular air jets impinging on a heat transfer surface parallel to the jet orifice plate are considered. The jet flow, after impingement, is constrained to exit in a single Jet array impingement flow distributions and heat transfer characteristics book along the channel formed by the jet orifice plate and the heat transfer surface.

Jet Array Impingement Jet array impingement flow distributions and heat transfer characteristics book Distributions Jet array impingement flow distributions and heat transfer characteristics book Heat Transfer Characteristics Effects of Initial Crossflow and Nonuniform Array Geometry L.

Florschuetz, D. Metzger, C. Su, Y. Isoda, and H. Tseng Arizona State University Tempe, Arizona Prepared for Lewis Research Center under Grant NSG-3 0 7 5File Size: 8MB. Heat transfer coefficients increase as cross-flow increases confirming the enhancement of heat transfer coefficients for channel flow behavior.

The jet structures on impingement in and around dimples seem to be affected by the bursting phenomena of the flow inside the dimples resulting in reduced impingement by:   Heat Transfer on Internal Surfaces of a Duct Subjected to Impingement of a Jet Array with Varying Jet Hole-Size and Spacing 1 February | Journal of Turbomachinery, Vol.No.

1 Flow and heat transfer of confined impingement jets cooling using Jet array impingement flow distributions and heat transfer characteristics book 3-D transient liquid crystal schemeCited by: HEAT TRANSFER DISTRIBUTIONS ON THE WALLS OF A NARROW CHANNEL WITH JET IMPINGEMENT AND CROSS FLOW Osama M.

Al-aqal, Ph.D. University of Pittsburgh, This study investigated the effect of the size of the jets, the number of jets, and jet-to-target plate spacing for the jet-issuing plate and target plate in the presence of a cross flow. The present work focuses on the heat transfer and pressure characteristics of a submerged multiple jet impingement system in the low Reynolds Number regime (large square array.

NASA Contractor Report NASA CR c.1 J et Array Impingement With Crossflow - Correlation of Streamwise Resolved Flow and Heat Transfer Distributions L. Mean and fluctuating heat transfer distributions from a heated surface to the impinging air jet are compared with local velocity measurements.

The literature to date has shown that the heat transfer to an impinging air jet is highly sensitive to each of the many experimental parame-ters that exist. The shape of the heat transfer distribution in.

An important factor affecting flow and heat transfer characteristics of multiple impinging jets in a confined space is the crossflow. Crossflow is defined as fluid flow in the perpendicular direction to the jet impingement flow.

It can be formed by either external flow or accumulating spent jet flow. The characteristics of fluid flow and heat transfer under an array of air impinging jets have been investigated in the open literature. In recent years, many investigators, have examined the heat transfer characteristics of an array of liquid impinging jets.

They focused mainly on the heat transfer under impinging jets for which crossflow effects, which potentially reduce the high stagnation heat transfer associated with impinging jets Cited by: The preceding studies have not yet considered the effect of air impingement jet arrays with non-identical jet-to-jet spacing and slot jet widths on the heat transfer from the heated plate.

applications where very uniform surface heat or mass transfer is required, the resulting high density of the jet array and corresponding small jet height may be impractical to construct and implement, and at small spacings jet-to-jet interaction may degrade efficiency.

Prior to the design of an impinging jet device, the heat transfer at the. Jet Arrays Turbulence and Heat transfer Characteristics The objective of this research is to provide a better understanding of the flow characteristics of a jet array with a self-induced crossflow formed in the impingement region of a confined jet array.

Abstract. Jet impingement is one of the best methods for achieving high heat transfer coefficient in single phase and has been a topic of active research for several decades, involving both experiments and computations. Most of the research on multiple jets have been carried out for an array of jets in the high Reynolds number by: Impinging jets provide a means of achieving high heat transfer coefficients both locally and on an area averaged basis.

The current work forms the first stage of a two part investigation of heat transfer distributions from a heated flat surface subject to an impinging air jet for Reynolds numbers f to 30, and non-dimensional surface to jet exit spacing, H/D, from Cited by:   In this study, an experimental and numerical study is carried out to investigate flow field and heat transfer characteristics of unconfined and confined arrays of four turbulent slot air jets issuing from the lower surface and impinging normally on the upper surface.

Pressure and temperature distributions on the surfaces were obtained for the nozzle-to-plate spacing Cited by: 9. Both single and multiple jet systems can be used, however, multiple jet systems offer higher and more uniform heat transfer.

A staggered array of mm diameter impingement jets with jet-to-jet spacing of D was examined where the spent fluid is extracted through one of six mm diameter extraction holes regularly located around each by: The jet flow, after impingement is constrained to exit in a single direction along the channel formed by the jet orifice plate and the impingement surface.

In addition to the crossflow which originates from the jets following impingement, an initial (independent) crossflow is present which approaches the array through an upstream extension of Cited by: Three-dimensional numerical study is conducted to investigate the heat transfer characteristics for the flow impingement cooling in the narrow passage based on cooling technology of turbine effects of the jet Reynolds number, impingement distance and initial cross-flow on heat transfer characteristic are s show that when other parameters remain unchanged local heat Cited by: 1.

In detail, to enhance the heat transfer in single and array jets, there is discussion on design and control of nozzle geometry, nozzle insertion, jet vibration, secondary injection, and suction flow. Multiple Jet Impingement Characteristic - Experimental ing flows, the jet array provides the designer with potential for a high de- gree of control of the distribution of surface heat transfer characteristics.

geometry on the internal impingement heat transfer characteristics including the effect of the Size: 5MB. heat transfer coefficient.

Wall pressure measurement and oil flow visualization on the target surface are performed to understand the flow pattern of impinging jet and wall jet. The effect of injection parameters, such as injection distance, jet-to-jet spacing and number of jets, on jet array impingement heat transfer is clarified.

NOMENCLATURE AFile Size: 1MB. A study of a large-scale model of an engine representative impingement cooling system has been performed. A series of tests were carried out to characterize the behavior of the system fully.

These included cold flow diagnostic tests to determine the pressure loss and the static pressure distribution, and flow visualization to assess surface by: A 10%-increasing and a 10%-decreasing jet diameter pattern are compared with a baseline geometry of uniform jet size distribution, indicating a considerable effect of varying jet diameter on the heat transfer level and the development of the generated by: Jet Impingement Heat Transfer.

This site provides information pertinent to the benchmark problem entitled "Confined and Submerged Liquid Jet Impingement," set for the ICHMT Symposium (CHT'01) - Advances in Computational Heat Transfer to be held in Palm Cove, Cairns, Queensland, Australia, May, Please use the links below to find more.

The correspondence between local fluid flow structures and convective heat transfer is a fundamental aspect that is not yet fully understood for multiple jet impingement. Therefore, flow field and heat transfer experiments are separately performed investigating mutual–jet interactions exposed in a self-gained crossflow.

The measurements are taken in two narrow impingement Cited by: Numerical study on flow and heat transfer characteristics of air-jet cooling system 10 July | Journal of Mechanical Science and Technology, Vol. 32, No. 12 Axisymmetric jet impingement on a dimpled surface: Effect of impingement location on flow field characteristicsCited by:   They found that the Nusselt number distribution over the plate becomes more uniform when the total heat transfer and the plate velocity decreases.

Later, Chattopadhyay and Saha used large Eddy simulation to investigate both the turbulent flow and the heat transfer resulting from a single slot jet impingement onto a moving hot isothermal plate Cited by:   This book chapter discussed impingement jet cooling.

Jet impingement achieves locally high heat transfer on an interested surface. For these reasons, the impinging jet cooling technique has been widely used in many industrial systems such as gas turbine cooling, rocket launcher cooling and high-density electrical equipment cooling in order to remove a large amount of by: 5.

heat load must be removed while maintaining a min-imum temperature or temperature difference within the system. For example, in some semiconductor laser systems, junction temperatures must be held below C while heat loads may reach 10 MW/m2.

Much attention has been given to jet impingement cooling of Size: KB. Two-dimensional arrays of circular air jets impinging on pdf heat transfer surface parallel to the jet orifice plate are considered.

In the experimental model the jet flow, after impingement, was constrained to exit in a single direction along the channel formed by the jet orifice plate and heat transfer surface.arrangements of Jet Impingement. 2. Jet with Square Edge Figure Square and chamfered download pdf nozzle.

Attalla et al investigated experimentally the effect of the nozzle geometry of square edge (nonchamfered) and with chamfered edge on local and average heat transfer distribution in free single circular air jet.

Recorded Temperature using IR.Jet impingement heat transfer can be an effective way at controlling ebook. The understanding of its dependence on various aerodynamic and geometric parameters is vital for proper implementation.

In published literature, there is a lack of detailed, empirical, single jet impingement heat transfer data with cross : Brian Roberts.