scholarly journals Innovations and Advancements in Heat & Mass Transfer: Celebrating the Legacy of Professor Ephraim M. Sparrow

2021 ◽  
Author(s):  
Sandra Boetcher ◽  
Raj M. Manglik
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Science Citation Index ◽  
Heat Mass Transfer ◽  
Citation Index ◽  
Academic Career ◽  
University Of Minnesota ◽  
Memorial Symposium ◽  
Wide Range ◽  
The University

Abstract The passing of Professor Ephraim M. Sparrow on August 1, 2019 left a large void in the worldwide heat and mass transfer community. To many in the field, he was an intellectual giant, who famously was the "most cited" mechanical engineering professor in the Science Citation Index for many decades. Many scholars, young and old, have encountered Professor Sparrow's multitude of works over a wide range of topics in standard academic textbooks, reference books, and eminent heat transfer journals. To his colleagues and students, 'Eph' was more than a giant in the field of heat transfer, he was an incredible mentor and a lifelong friend who was passionate about the multifaceted area of thermal science and never stopped wanting to learn. To celebrate Eph's multitude of contributions, a memorial symposium was held at the University of Minnesota, where he had spent his entire professional academic career.

Heat and Mass Transfer in an Incompressible Turbulent Boundary Layer

1972 ◽  
Vol 94 (1) ◽  
pp. 23-28 ◽  
Author(s):  
E. Brundrett ◽  
W. B. Nicoll ◽  
A. B. Strong
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Mass Transfer ◽  
Porous Plate ◽  
Mixing Length ◽  
Two Dimensional ◽  
Transfer Data ◽  
Incompressible Turbulent Boundary Layer ◽  
Wide Range ◽  
Incompressible Boundary

The van Driest damped mixing length has been extended to account for the effects of mass transfer through a porous plate into a turbulent, two-dimensional incompressible boundary layer. The present mixing length is continuous from the wall through to the inner-law region of the flow, and although empirical, has been shown to predict wall shear stress and heat transfer data for a wide range of blowing rates.

Prescribed burning for lowland black spruce regeneration in northern Minnesota

1984 ◽  
Vol 14 (1) ◽  
pp. 107-113 ◽  
Author(s):  
Scott E. Aksamit ◽  
Frank D. Irving
Keyword(s):  
Prescribed Burning ◽  
Black Spruce ◽  
Controlled Study ◽  
University Of Minnesota ◽  
Feather Moss ◽  
Wide Range ◽  
Labrador Tea ◽  
Tall Shrub ◽  
The University ◽  
Larger Sample

Concern over the variability of black spruce (Piceamariana (Mill.) B.S.P.) regeneration on peatlands in northern Minnesota following prescribed burning led to a cooperative study between the University of Minnesota and the Minnesota Department of Natural Resources. Twenty-seven black spruce cutovers on State lands that had been prescribed burned and either seeded or left to regenerate naturally were sampled. These were stratified into sphagnum – Labrador-tea – leather-leaf (SPHG) sites (10), feather moss (FM) sites (9), and alder – graminoid – other tall shrub (ALDR) sites (8). Results indicate that fire was not necessary to regenerate SPHG sites. FM sites required fire to modify unfavorable seedbeds and to reduce competition. Best results were obtained by burning when the upper layers of the peat were highly desiccated. ALDR sites occupied a wide range of ecological conditions which led to highly variable regeneration results. A larger sample size and possibly more carefully controlled study conditions are needed to fully understand ALDR site regeneration. Seeding results were uncertain for all sites.

scholarly journals Highly Resolved Distribution of Heat Transfer for Turbine Leading Edge Film Cooling Including Reynolds Number and Blowing Rate Effects

1998 ◽  
Author(s):  
K. Jung ◽  
D. K. Hennecke
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Reynolds Number ◽  
Film Cooling ◽  
Heat Mass Transfer ◽  
Leading Edge ◽  
Transfer Coefficients ◽  
Complex Flow ◽  
Long Distance ◽  
Naphthalene Sublimation Technique

The effect of leading edge film cooling on heat transfer was experimentally investigated using the naphthalene sublimation technique. The experiments were performed on a symmetrical model of the leading edge suction side region of a high pressure turbine blade with one row of film cooling holes on each side. Two different lateral inclinations of the injection holes were studied: 0° and 45°. In order to build a data base for the validation and improvement of numerical computations, highly resolved distributions of the heat/mass transfer coefficients were measured. Reynolds numbers (based on hole diameter) were varied from 4000 to 8000 and blowing rate from 0.0 to 1.5. For better interpretation, the results were compared with injection-flow visualizations. Increasing the blowing rate causes more interaction between the jets and the mainstream, which creates higher jet turbulence at the exit of the holes resulting in a higher relative heat transfer. This increase remains constant over quite a long distance dependent on the Reynolds number. Increasing the Reynolds number keeps the jets closer to the wall resulting in higher relative heat transfer. The highly resolved heat/mass transfer distribution shows the influence of the complex flow field in the near hole region on the heat transfer values along the surface.

Heat Transfer Enhancements in Rotating Two-Pass Coolant Channels With Profiled Ribs: Part 2—Detailed Measurements

2000 ◽  
Vol 123 (1) ◽  
pp. 107-114 ◽  
Author(s):  
D. E. Nikitopoulos ◽  
V. Eliades ◽  
S. Acharya
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Reynolds Number ◽  
Heat Mass Transfer ◽  
Blockage Ratio ◽  
Average Heat ◽  
Rotation Numbers ◽  
Naphthalene Sublimation ◽  
Side Walls ◽  
Made In

Detailed heat/mass transfer distributions are presented inside a two-pass rotating ribbed coolant channel for two profiled-rib configurations. Several profiled-rib configurations have been studied (Acharya et al., 2000), and it was found that the best performance was achieved by saw-tooth ribs, and a pyramid–valley rib combination. The profiled ribs were placed directly opposite to each other on the leading and trailing surfaces. Smooth side walls were used in all the experiments. Heat transfer measurements were compared with straight ribs of equal blockage ratio. The measurements were made in a two-pass rotating facility using the naphthalene sublimation mass transfer technique, which provides highly resolved surface distributions. The results presented are for a Reynolds number of 30,000, two rotation numbers (0 and 0.3), and include average heat/mass transfer over the entire inter-rib module as well as detailed heat/mass transfer contours for two profiled-rib cases. Significant enhancement of up to 25 percent in heat/mass transfer was obtained with the pyramid–valley and saw-tooth shaped ribs under rotating conditions.

Local Heat/Mass Transfer Characteristics on a Rotating Blade With Flat Tip in a Low-Speed Annular Cascade—Part II: Tip and Shroud

2005 ◽  
Vol 128 (1) ◽  
pp. 110-119 ◽  
Author(s):  
Dong-Ho Rhee ◽  
Hyung Hee Cho
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Flow Velocity ◽  
Rotational Speed ◽  
Heat Mass Transfer ◽  
Local Heat ◽  
Incoming Flow ◽  
Transfer Coefficients ◽  
Low Speed ◽  
Annular Cascade

The local heat/mass transfer characteristics on the tip and shroud were investigated using a low speed rotating turbine annular cascade. Time-averaged mass transfer coefficients on the tip and shroud were measured using a naphthalene sublimation technique. A low speed wind tunnel with a single stage turbine annular cascade was used. The turbine stage is composed of sixteen guide plates and blades. The chord length of blade is 150 mm and the mean tip clearance is about 2.5% of the blade chord. The tested Reynolds number based on inlet flow velocity and blade chord is 1.5×105 and the rotational speed of the blade is 255.8 rpm at design condition. The results were compared with the results for a stationary blade and the effects of incidence angle of incoming flow were examined for incidence angles ranging from −15 to +7deg. The off-design test conditions are obtained by changing the rotational speed with a fixed incoming flow velocity. Flow reattachment on the tip near the pressure side edge dominates the heat transfer on the tip surface. Consequently, the heat/mass transfer coefficients on the blade tip are about 1.7 times as high as those on the blade surface and the shroud. However, the heat transfer on the tip is about 10% lower than that for the stationary case due to reduced leakage flow with the relative motion. The peak regions due to the flow reattachment are reduced and shifted toward the trailing edge and additional peaks are formed near the leading edge region with decreasing incidence angles. But, quite uniform and high values are observed on the tip with positive incidence angles. The time-averaged heat/mass transfer on the shroud surface has a level similar to that of the stationary cases.

Heat Transfer Enhancements in Rotating Two-Pass Coolant Channels With Profiled Ribs: Part 2 — Detailed Measurements

2000 ◽  
Author(s):  
D. E. Nikitopoulos ◽  
V. Eliades ◽  
S. Acharya
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Reynolds Number ◽  
Heat Mass Transfer ◽  
Blockage Ratio ◽  
Average Heat ◽  
Rotation Numbers ◽  
Naphthalene Sublimation ◽  
Side Walls ◽  
Made In

Detailed heat/mass transfer distributions are presented inside a two-pass rotating ribbed coolant channel for two profiled-rib configurations. Several profiled-rib configurations have been studied (Acharya et al.; 2000), and it was found that the best performance was achieved by saw-tooth ribs, and a pyramid–valley rib combination. The profiled ribs were placed directly opposite to each other on the leading and trailing surfaces. Smooth side walls were used in all the experiments. Heat transfer measurements were compared with straight ribs of equal blockage ratio. The measurements were made in a two-pass rotating facility using the naphthalene sublimation mass transfer technique which provides highly resolved surface distributions. The results presented are for a Reynolds number of 30,000 two Rotation numbers (0 and 0.3) and include average heat/mass transfer over the entire inter-rib-module as well as detailed heat/mass transfer contours for two profiled-rib cases. Significant enhancements of up to 25% in heat/mass transfer was obtained with the pyramid-valley, and saw-tooth shaped ribs under rotating conditions.

Heat and Mass Transfer Caused by a Laminar Channel Flow Equipped With a Synthetic Jet Array

2010 ◽  
Author(s):  
Zdeneˇk Tra´vni´cˇek ◽  
Petra Dancˇova´ ◽  
Jozef Kordik ◽  
Toma´sˇ Vit ◽  
Miroslav Pavelka
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Reynolds Number ◽  
Heat Transfer Enhancement ◽  
Channel Flow ◽  
Heat Mass Transfer ◽  
Low Reynolds Number ◽  
Transfer Enhancement ◽  
Laminar Channel Flow ◽  
Low Reynolds

Low-Reynolds-number laminar channel flow is used in various heat/mass transfer applications, such as cooling and mixing. A low Reynolds number implies a low intensity of heat/mass transfer processes, since they rely only on the gradient diffusion. To enhance these processes, an active flow control by means of synthetic (zero-net-mass-flux) jets is proposed. This arrangement can be promising foremost in microscale. The present study is experimental in which a Reynolds number range of 200–500 is investigated. Measurement was performed mainly in air as the working fluid by means of hot-wire anemometry and the naphthalene sublimation technique. PIV experiments in water are also discussed. The experiments were performed in macroscale at the channel cross-section (20×100)mm and (40×200)mm in air and water, respectively. The results show that the low Reynolds number channel flow can be actuated by an array of synthetic jets, operating near the resonance frequency. The control effect of actuation and the heat transfer enhancement was quantified. The stagnation Nusselt number was enhanced by 10–30 times in comparison with the non-actuated channel flow. The results indicate that the present arrangement can be a useful tool for heat transfer enhancement in various applications, e.g., cooling and mixing.

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