Download or read book An Experimental Investigation of Heat Transfer in an Orthogonally Rotating Channel Roughened with 45 Degree Criss cross Ribs on Two Opposite Walls written by M. E. Taslim and published by . This book was released on 1990 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbine blade cooling is imperative in advanced aircraft engines. The extremely hot gases that operate within the turbine section require turbine blades to be cooled by a complex cooling circuit. This cooling arrangement increases engine efficiency and ensures blade materials a longer creep life. One principle aspect of the circuit involves serpentine internal cooling passes throughout the core of the blade. Roughening the inside surfaces of these cooling passages with turbulence promoters provides enhanced heat transfer rates from the surface. The purpose of this investigation was to study the effect of rotation, aspect ratio, and turbulator roughness on heat transfer in these rib-roughened passages. The investigation was performed in an orthogonally rotating setup to simulate the actual rotation of the cooling passages. Single-pass channels, roughened on two opposite walls, with turbulators positioned at 45 deg angle to the flow, in a criss-cross arrangement, were studied throughout this experiment. The ribs were arranged such that their pitch-to-height ratio remained at a constant value of 10. An aspect ratio of unity was investigated under three different rib blockage ratios (turbulator height/channel hydraulic diameter) of 0.1333, 0.25, and 0.3333. A channel with an aspect ratio of 2 was also investigated for a blockage ratio of 0.25. Air was flown radially outward over a Reynolds number range of 15,000 to 50,000. The rotation number was varied from 0 to 0.3. Stationary and rotating cases of identical geometries were compared. Results indicated that rotational effects are more pronounced in turbulated passages of high aspect and low blockage ratios for which a steady increase in heat transfer coefficient is observed on the trailing side as rotation number increases while the heat transfer coefficient on the leading side shows a steady decrease with rotation number. However, the all-smooth-wall classical pattern of heat transfer coefficient variation on the leading and trailing sides is not followed for smaller aspect ratios and high blockage ratios when the relative artificial roughness is high.
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 Paper written by and published by . This book was released on 2001 with total page 506 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book ASME Technical Papers written by and published by . This book was released on 2001 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Journal of Turbomachinery written by and published by . This book was released on 1994 with total page 800 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Lecture series written by and published by . This book was released on 2000 with total page 726 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Heat Transfer in Gas Turbines written by Bengt Sundén and published by Witpress. This book was released on 2001 with total page 544 pages. Available in PDF, EPUB and Kindle. Book excerpt: This title presents and reflects current active research on various heat transfer topics and related phenomena in gas turbine systems. It begins with a general introduction to gas turbine heat transfer, before moving on to specific areas.
Download or read book AIAA Journal written by American Institute of Aeronautics and Astronautics and published by . This book was released on 2003 with total page 1252 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Annual Review of Heat Transfer written by Chang Lin Tien and published by . This book was released on 1998 with total page 474 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Journal of Heat Transfer written by and published by . This book was released on 2007 with total page 712 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1991 with total page 786 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 32nd AIAA ASME SAE ASEE Joint Propulsion Conference Exhibit written by and published by . This book was released on 1996 with total page 526 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Experimental Investigation of Heat Transfer Coefficients in a Spanwise Rotating Channel with Two Opposite Rib roughened Walls written by M. E. Taslim and published by . This book was released on 1989 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Turbulent Heat Transfer in a Trapezoidal Channel with Transverse and V shaped Ribs on Two Opposite Walls written by Karthik Subramanian and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This study investigates the turbulent heat transfer and friction in a trapezoidal channel with opposite walls roughened with transverse and v-shaped ribs. The roughened channel depicts the internal cooling passage of an aerofoil near the trailing edge. The various configurations investigated for this study are smooth channel, channel with 90° transverse ribs and channel with v-shaped ribs angled at 45°. The pitch-to-height ratio (P/e), rib height-to-hydraulic diameter ratio (e/D[subscript]h) and the aspect ratio (W/e) were maintained at 12, 0.1906 and 1, respectively. The configuration was tested for Reynolds number ranging from 7,000 to 40,000. The 45° rib was found to produce the maximum heat transfer and minimum pressure loss.
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 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 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.
