Download or read book Detailed Understanding of Flow Heat Transfer and Pressure Drop Behavior in a Square Channel with 45 Deg Ribs written by Lumaya Ahmed and published by . This book was released on 2018 with total page 183 pages. Available in PDF, EPUB and Kindle. Book excerpt: Internal Duct Cooling (IDC) with rib turbulators is one of the common cooling techniques applied inside the turbine airfoils. It is very important for the gas turbine industry to design and develop an optimized cooling channel that maximizes the amount of heat removed, while simultaneously minimizing the pressure drop for a target overall cooling effectiveness. Angled ribs perform superior to the transverse ribs due to additional secondary flow associated with them. However, they result in a highly non-homogenous heat transfer distribution, which is a manifestation of the complex, turbulent flow field inside the channel. It is very important to comprehend the secondary flow physics to characterize the heat transfer distribution in such angled ribbed channels. Additionally, due to the manufacturing constraint, the gas turbine industry encounters a challenge to make ribs edge sharp and results in ribs with rounded edges. The one of the main objectives of the present study is to provide a fundamental understanding of the flow physics on the heat transfer and pressure drop behavior in 45° ribbed channels both with sharp and rounded-edge ribs. It is found that the secondary flow has a significant effect on the heat transfer behavior for both types of ribs. There is a great need of high-fidelity PIV flow field data in the inter-rib space for an angled ribbed channel which can be used for CFD validation, especially for LES. The current study provides benchmarking flow field data in the inter-rib space in a square channel with 45° ribs using stereoscopic PIV technique. Besides the experiments, numerical studies were also conducted by using LES and different RANS models. The LES results show an excellent prediction capability for aerothermal behavior in such channels. However, the prediction capability of RANS models is found to be inconsistent for different rib configurations and flow conditions.
Download or read book Journal of Heat Transfer written by and published by . This book was released on 2008 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Heat Transfer Friction and Turbulent Analysis on Single Ribbed wall Square Channel written by Christopher E. Vergos and published by . This book was released on 2017 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental investigation of heat transfer and friction behavior for a fully developed flow in a non-rotating square channel was conducted under a wide range of Reynolds numbers from 6,000 to 180,000. The rig used in this study was a single ribbed wall variant of Ahmed et al.'s [1] rig from which results of this rig were compared. Ahmed et al.'s rig was a replica of Han et al.'s square channel [2] used to validate their work, and expand the Reynolds number range for both heat transfer and friction data. The test section was 22 hydraulic diameters (D[subscript h]) long, and made of four aluminum plates. One rib roughened bottom wall, and three smooth walls bounded the flow. Glued brass ribs oriented at 45° to the flow direction, with a ratio of rib height to channel hydraulic diameter (e/D[subscript h]) and a ratio of pitch to rib height (p/e) of 0.063 and 10, respectively, lined the bottom wall. A 20Dh long acrylic channel with a continuation of the test section's interior was attached at the inlet of the test section to confirm the fully developed flow. Heat transfer tests were conducted in a Reynolds number range of 20,000 to 150,000.
Download or read book Heat Transfer and Pressure Drop Measurement for Square Channels with V shape Ribs at High Reynolds Numbers written by Nawaf Yahya Alkhamis and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In previous studies, the thermal performance of ribbed channels was studied for Reynolds numbers up to 100,000 with different rib shapes. In more recent studies, the thermal performance of ribbed channels was studied up to Reynolds numbers of 400,000 for angled ribs to cover the range of internal cooling inside land-based gas turbines. Previous studies also show that the thermal performance of V-shaped ribs is better than the angled ribs. In this study, the Reynolds number from 30,000 to 400,000 is studied with V-shaped ribs. The blockage ratio e/D is 0.1, 0.15, and 0.18 and spacing ratio P/e is 5, 7.5, and 10. The results show that the Nusselt number enhancement decreases when the Reynolds number increases. The friction factor is found to be independent of The Reynolds number. The thermal performance decreases when the Reynolds number increases. Correlations for the Nusselt number and the friction factor as function of Re, e/D, and P/e are developed.
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1988 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Journal of Thermophysics and Heat Transfer written by and published by . This book was released on 2007 with total page 868 pages. Available in PDF, EPUB and Kindle. Book excerpt: This journal is devoted to the advancement of the science and technology of thermophysics and heat transfer through the dissemination of original research papers disclosing new technical knowledge and exploratory developments and applications based on new knowledge. It publishes papers that deal with the properties and mechanisms involved in thermal energy transfer and storage in gases, liquids, and solids or combinations thereof. These studies include conductive, convective, and radiative modes alone or in combination and the effects of the environment.
Download or read book Measurements of Heat Transfer and Pressure Drop in a Rectangular Channel with Repeated Perforated Ribs of Various Widths written by Jenn - Jiang Hwang and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presented at the International Gas Turbine & Aeroegine Congress & Exhibition, Orlando, FL, Jun 2-Jun 5, 1997.
Download or read book Introduction to Heat Transfer written by Bengt Sundén and published by WIT Press. This book was released on 2012 with total page 365 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presenting the basic mechanisms for transfer of heat, this book gives a deeper and more comprehensive view than existing titles on the subject. Derivation and presentation of analytical and empirical methods are provided for calculation of heat transfer rates and temperature fields as well as pressure drop. The book covers thermal conduction, forced and natural laminar and turbulent convective heat transfer, thermal radiation including participating media, condensation, evaporation and heat exchangers. This book is aimed to be used in both undergraduate and graduate courses in heat transfer and thermal engineering. It can successfully be used in R & D work and thermal engineering design in industry and by consultancy firms
Download or read book Heat Transfer and Pressure Drop in Square Duct with Two Opposite Repeated Rib roughened Walls written by Chiang-Kuo Lei and published by . This book was released on 1983 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Previews of Heat and Mass Transfer written by and published by . This book was released on 1989 with total page 632 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of Rib Aspect Ratio on Heat Transfer and Friction in Rectangular Channels written by Lucky Vo Tran and published by . This book was released on 2011 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: The heat transfer and friction augmentation in the fully developed portion of a 2:1 aspect ratio rectangular channel with orthogonal ribs at channel Reynolds numbers of 20,000, 30,000, and 40,000 is studied both experimentally and computationally. Ribs are applied to the two opposite wide walls. The rib aspect ratio is varied systematically at 1, 3, and 5, with a constant rib height and constant rib pitch (rib-pitch-to-rib-height ratio of 10). The purpose of the study is to extend the knowledge of the performance of rectangular channels with ribs to include high aspect ratio ribs. The experimental investigation is performed using the transient Thermochromic Liquid Crystals technique to measure the distribution of the local Nusselt numbers on the ribbed walls. Overall channel pressure drop and friction factor augmentation is also obtained with the experimental setup. A numerical simulation is also performed by solving the 3-D Reynolds- averaged Navier-Stokes equations using the realizable-k-[epsilon] turbulence model for closure. Flow visualization is obtained from the computational results as well as numerical predictions of local distributions of Nusselt numbers and overall channel pressure drop. Results indicate that with increasing rib width, the heat transfer augmentation of the ribbed walls decreases with a corresponding reduction in channel pressure drop.
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1998 with total page 984 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proceedings of the ASME Heat Transfer Division written by and published by . This book was released on 2001 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Aspect Ratio Effect on Heat Transfer in Rotating Two pass Rectangular Channels with Smooth Walls and Ribbed Walls written by Wen-Lung Fu and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This study experimentally investigates the effects of rotation, the buoyancy force, and the channel aspect ratio on heat transfer in two-pass rotating rectangular channels. The experiments are conducted with two surface conditions: smooth walls and 45° angled ribbed walls. The channel aspect ratios include 4:1, 2:1, 1:1, 1:2 and 1:4. Four Reynolds numbers are studied: 5000, 10000, 25000 and 40000. The rotation speed is fixed at 550 rpm for all tests, and for each channel, two channel orientations are studied: 90° and 45° or 135°, with respect to the plane of rotation. Rib turbulators are placed on the leading and trailing walls of the channels at an angle of 45° to the flow direction. The ribs have a 1.59 by 1.59 mm square cross section, and the rib pitch-to-height ratio (P/e)is 10 for all tests. The effects of the local buoyancy parameter and channel aspect ratio on the regional Nusselt number ratio are presented. Pressure drop data are also measured for both smooth and ribbed channels in rotating and non-rotating conditions. The results show that increasing the local buoyancy parameter increases the Nusselt number ratio on the trailing surface and decreases the Nusselt number ratio on the leading surface in the first pass for all channels. However, the trend of the Nusselt number ratio in the second pass is more complicated due to the strong effect of the 180° turn. Results are also presented for this critical turn region of the two-pass channels. In addition to these regions, the channel averaged heat transfer, friction factor, and thermal performance are determined for each channel. With the channels having comparable Nusselt number ratios, the 1:4 channel has the superior thermal performance because it incurs the least pressure penalty. In this study, the author is able to systematically analyze, correlate, and conclude the thermal performance comparison with the combination of rotation effectson five different aspect ratio channels with both smooth walls and rib turbulated walls.
Download or read book Heat Transfer and Flow in a Square Duct with Ribs written by John Charles Paschall and published by . This book was released on 1995 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Pressure Drop and Heat Transfer Study of Two phase Flow in Small Channels written by Thanh Nhon Tran and published by . This book was released on 1998 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Heat Transfer and pressure drop of air in forced convection across triangular pitch banks of finned tubes written by Dennis J. Ward and published by . This book was released on 1956 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt:
