Mass and Heat Transfer From an Enclosed Rotating Disk With and Without Source Flow

1963 ◽  
Vol 85 (2) ◽  
pp. 153-162 ◽  
Author(s):  
Frank Kreith ◽  
E. Doughman ◽  
H. Kozlowski
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Rotating Disk ◽  
Reynolds Numbers ◽  
Correlation Equation ◽  
Rotating Disks ◽  
Transfer Coefficients ◽  
Transfer Rates ◽  
Smoke Visualization ◽  
Source Flow

The heat-transfer characteristics of a partially enclosed rotating disk have been investigated experimentally by means of a mass-transfer analog. Mass-transfer rates to air from naphthalene coated disks of 4 and 8 in. diameter were measured at speeds between zero and 10,000 rpm and the influence of the spacing between the rotating disk and its housing was investigated with and without source flow. From the experimental results a dimensionless correlation equation suitable for predicting average heat and mass-transfer coefficients for rotating disks with source flow in turbulent flow at rotational Reynolds numbers up to 4 × 105 was deduced. The flow pattern was investigated by means of a hot wire, a smoke visualization technique, and the china clay method.

Heat Transfer From an Asymmetrically Heated Channel Partially Enclosing a Rotating Disk

1995 ◽  
Vol 117 (1) ◽  
pp. 79-84 ◽  
Author(s):  
R. R. Schmidt ◽  
P. Patel
Keyword(s):  
Heat Transfer ◽  
Rotating Disk ◽  
Reynolds Numbers ◽  
Correlation Equation ◽  
Transfer Coefficients ◽  
Naphthalene Sublimation Technique ◽  
Heated Channel ◽  
Naphthalene Sublimation ◽  
Parallel Surfaces ◽  
Insight Into

Experiments have been performed to determine the heat transfer from an asymmetrically heated channel partially enclosing a vertically oriented rotating disk. Parallel rectangular surfaces enclose the rear portion of a disk (slightly less than 1/2 of the disk is enclosed) allowing air to enter and exit the perimeter of the channel, except the rear vertical portion bridging the two parallel surfaces. The experiments encompassed data runs where one of the parallel walls was isothermal and the other was adiabatic. The experiments encompassed a range of spacings between the rotating disk and the adjacent parallel surfaces and a range of rotational speeds varying by a factor of 30. The experiments were performed using the naphthalene sublimation technique. From the experimental results a dimensionless correlation equation suitable for predicting average heat and mass transfer coefficients of the enclosing surfaces for various rotational Reynolds numbers and disk-to-wall spacings was deduced. Finally, to gain some insight into the air flow pattern along the enclosing walls, a visual flow technique was employed, the results of which will be described herein.

Heat and Mass Transfer From a Rotating Disk

1959 ◽  
Vol 81 (2) ◽  
pp. 95-103 ◽  
Author(s):  
F. Kreith ◽  
J. H. Taylor ◽  
J. P. Chong
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Rotating Disk ◽  
Heat Transfer Process ◽  
Transfer Coefficients ◽  
Transfer Rates ◽  
Turbulent Vortex ◽  
Heat Transfer Coefficients ◽  
Adiabatic Surface ◽  
Measured Mass

The analogy between heat, mass, and momentum transfer is applied to a rotating disk. Experimentally measured mass-transfer rates from a disk rotating in an infinite environment under laminar and turbulent conditions are related to the corresponding heat-transfer process by means of an analogy method. The experimental analog is shown to eliminate difficulties associated with accurate measurements of heat-transfer coefficients. Experimental data on the effect of an adiabatic surface placed at various distances parallel to the disk on the transfer rate from the disk are presented. Observations of some unusual flow patterns resulting from Goertler type vortexes in the transition regime and from some as yet unexplained turbulent vortex phenomena are also reported.

Measurement and Analysis of Laminar Heat Transfer Coefficients in Micro and Mini-Scale Ducts and Channels

2014 ◽  
Author(s):  
Y. S. Muzychka ◽  
M. Ghobadi
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Reynolds Numbers ◽  
Transfer Coefficients ◽  
Constant Wall Temperature ◽  
Fully Developed Flow ◽  
Transfer Rates ◽  
Heat Transfer Coefficients ◽  
Advantages And Disadvantages ◽  
Nusselt Numbers

Heat transfer in micro and mini-scale ducts and channels is considered. In particular, issues of thermal performance are considered in systems with constant wall temperature at low to moderate Reynolds numbers or small dimensional scales which lead to conditions characteristic of thermally fully developed flows or within the transition region leading to thermally fully developed flows. An analysis of two approaches to representing experimental data is given. One using the traditional Nusselt number and another using the dimensionless mean wall flux. Both approaches offer a number of advantages and disadvantages. In particular, it is shown that while good data can be obtained which agree with predicted heat transfer rates, the same data can be problematic if one desires a Nusselt number. Other issues such as boundary conditions pertaining to measuring thermally developing and fully developed flow Nusselt numbers are also discussed in detail.

Convective Heat Transfer From a Free Rotating Disk Subjected to a Forced Crossflow

2014 ◽  
Author(s):  
Christian Helcig ◽  
Stefan aus der Wiesche
Keyword(s):  
Heat Transfer ◽  
Flow Field ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Rotating Disk ◽  
Reynolds Numbers ◽  
Forced Flow ◽  
High Angular Resolution ◽  
Angle Of Incidence ◽  
Transfer Coefficients

The understanding of the heat transfer and flow field behavior of rotating systems is essential from a fundamental point of view and for turbo machinery design. The majority of the publications considers enclosed rotating disk systems and only little is known about the convective heat transfer of free rotating disk systems in a forced flow. In this paper, a free rotating disk system, with particular look on the angle of incidence was investigated. The convective heat transfer from a rotating disk depends at least on three characteristic variables, namely the crossflow, rotational Reynolds numbers and the angle of incidence which are determining the mean Nusselt number. A clear study of the symmetry behavior of the flow field was conducted based on the measurement of the convective heat transfer coefficients. The angle of incidence was scanned with high angular resolution over the entire range between the both extreme cases of a perpendicular disk and a disk in a parallel forced flow. A large number of crossflow and rotational Reynolds numbers were covered by the experiments, too. Based on the experimental and theoretical results, a discussion of the different phenomena and heat transfer regimes is given in this paper.

Flow Phenomena of Partially Enclosed Rotating Disks

1960 ◽  
Vol 82 (3) ◽  
pp. 539-549 ◽  
Author(s):  
L. A. Maroti ◽  
G. Deak ◽  
F. Kreith
Keyword(s):  
Flow Pattern ◽  
Side Wall ◽  
Rotating Disk ◽  
Reynolds Numbers ◽  
Frictional Torque ◽  
Gap Size ◽  
Rotating Disks ◽  
Disk Speed ◽  
Flow Phenomena ◽  
Source Flow

The flow of air in the space between a rotating disk and a stationary side wall placed parallel to its surface has been investigated over a range of Reynolds numbers from 3 × 105 to 6 × 106 at clearance-to-diameter ratios from 0.0125 to 0.0625. When the size of the stationary side wall was larger than the diameter of the rotating disk the flow in the gap was found to be periodic; several distinct and separate inflow and outflow regions were observed to rotate in the same direction as the disk, but at a slower speed. The number of flow regions was found to be a function of the disk speed and the gap size. The frictional torque on the housing was also measured and the effect of source flow on the flow pattern was studied qualitatively.

Coefficients of Heat and Mass Transfer in a Packed Bed Suitable for Solar Regeneration of Aqueous Lithium Chloride Solutions

1984 ◽  
Vol 106 (4) ◽  
pp. 387-392 ◽  
Author(s):  
G. O. G. Lo¨f ◽  
T. G. Lenz ◽  
S. Rao
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Lithium Chloride ◽  
Packed Column ◽  
Packed Bed ◽  
Transfer Coefficients ◽  
Transfer Rates ◽  
Vapor Transfer ◽  
Lithium Chloride Solution ◽  
Water Vapor Transfer

Reconcentration of a lithium chloride solution in an open-cycle absorption chiller can be accomplished by passing solar heated air through a packed column to which the dilute solution is supplied. Following a theoretical study of heat transfer and water vapor transfer rates in the column, experimental measurement of those rates was made. Heat transfer and mass transfer coefficients are correlated with rates of air and liquid flow, and with temperatures of air and liquid supply. Performance data are presented and commercial design and operating requirements are suggested.

Heat Transfer in a Surfactant Drag-Reducing Solution—A Comparison With Predictions for Laminar Flow

2005 ◽  
Vol 128 (6) ◽  
pp. 557-563 ◽  
Author(s):  
Paul L. Sears ◽  
Libing Yang
Keyword(s):  
Heat Transfer ◽  
Laminar Flow ◽  
Reynolds Numbers ◽  
High Heat ◽  
High Heat Flux ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Nusselt Numbers ◽  
Drag Reducing Additive ◽  
Good Agreement

Heat transfer coefficients were measured for a solution of surfactant drag-reducing additive in the entrance region of a uniformly heated horizontal cylindrical pipe with Reynolds numbers from 25,000 to 140,000 and temperatures from 30to70°C. In the absence of circumferential buoyancy effects, the measured Nusselt numbers were found to be in good agreement with theoretical results for laminar flow. Buoyancy effects, manifested as substantially higher Nusselt numbers, were seen in experiments carried out at high heat flux.

Flow Past a Spinning Sphere With Surface Blowing and Heat Transfer

2005 ◽  
Vol 127 (1) ◽  
pp. 163-171 ◽  
Author(s):  
H. Niazmand ◽  
M. Renksizbulut
Keyword(s):  
Heat Transfer ◽  
Three Dimensional ◽  
Flow Regimes ◽  
Solid Sphere ◽  
Temporal Variations ◽  
Transfer Coefficients ◽  
Transfer Rates ◽  
Particle Spin ◽  
Flow Past ◽  
Angular Velocities

Computations are performed to determine the transient three-dimensional heat transfer rates and fluid forces acting on a stream-wise spinning sphere for Reynolds numbers in the range 10⩽Re⩽300 and angular velocities Ωx⩽2. In this Re range, classical flow past a solid sphere develops four different flow regimes, and the effects of particle spin are studied in each regime. Furthermore, the combined effects of particle spin and surface blowing are examined. Sphere spin increases drag in all flow regimes, while lift shows a nonmonotonic behavior. Heat transfer rates are not influenced by spin up to a certain Ωx but increase monotonically thereafter. An interesting feature associated with sphere spin is the development of a special wake regime such that the wake simply spins without temporal variations in its shape. For this flow condition, the magnitudes of the lift, drag, and heat transfer coefficients remain constant in time. Correlations are provided for drag and heat transfer.

Heat Transfer in Separated, Reattached, and Redevelopment Regions Behind a Double Step at Entrance to a Flat Duct

1967 ◽  
Vol 89 (2) ◽  
pp. 163-167 ◽  
Author(s):  
E. G. Filetti ◽  
W. M. Kays
Keyword(s):  
Heat Transfer ◽  
Local Heat Transfer ◽  
Reynolds Numbers ◽  
Local Heat ◽  
Duct Flow ◽  
Double Step ◽  
Maximum Heat ◽  
Transfer Rates ◽  
Maximum Heat Transfer ◽  
Flow Cross

Experimental data are presented for local heat transfer rates near the entrance to a flat duct in which there is an abrupt symmetrical enlargement in flow cross section. Two enlargement area ratios are considered, and Reynolds numbers, based on duct hydraulic diameter, varied from 70,000 to 205,000. It is found that such a flow is characterized by a long stall on one side and a short stall on the other. Maximum heat transfer occurs in both cases at the point of reattachment, followed by a decay toward the values for fully developed duct flow. Empirical equations are given for the Nusselt number at the reattachment point, correlated as functions of duct Reynolds number and enlargement ratio.

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