Download or read book Simulation of Flow Through Low pressure Linear Turbine Cascade Using Multi block Structured Grid written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Reynolds number for the flow through LPT at cruise conditions is much lower than that at the take-off conditions. This low-Re flow has a great tendency to undergo separation on the suction surface of the turbine blade when an adverse pressure gradient is encountered. This prevailing flow separation is detrimental to the performance of the LPT. Hence, low-pressure turbine (LPT) stage in aircraft engines undergo significant losses during cruise conditions. Therefore, accurate prediction of flow separation is crucial for an effective design of LPT blade, and is achieved in the present work using a high-order accurate numerical solution procedure. The accurate prediction of flow separation is necessary for implementing flow control techniques, passive or active, to possibly delay or prevent the occurrence of flow separation in the low-pressure turbine stage in an aircraft engine. A multi-block, periodic, structured grid of multiple topologies generated by the grid generation software, GRIDPRO, is used for the present numerical analysis. The three-dimensional, unsteady, full Navier-Stokes equations are solved to analyze the flow. A MPI-based higher-order, parallel, chimera Large-Eddy Simulation (LES), version of the FDL3DI flow solver, developed by the Air Force Research Laboratory at Wright Patterson Air Force Base, is extended for the present turbo-machinery application. A sixth-order accurate compact-difference scheme is usual for the spatial discretization, coupled with tenth-order filtering to minimize the numerical oscillations in the flow solution and maintain numerical stability, along with second-order accurate temporal discretization. Also examined is the effect of grid density and the location of the upstream inflow boundary ... Finally, the baseline simulation study of flow over a circular cylinder at ReD = 13,400 is performed as a starting step for the future study of implementation of flow control techniques for preventing or delaying the flow separation.
Download or read book Analysis of Separated Flow in a Low pressure Turbine Linear Cascade Using Multi block Structured Grid written by Pavan K. Mutnuri and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Study of Separated Flow Through a Low pressure Turbine Cascade written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Low-pressure turbines (LPT) experience large changes in chord Reynolds number as the turbine engine operates from take-off to cruise conditions. Due to prevailing conditions at high altitude cruise, the Reynolds number reduces drastically. At low Reynolds numbers, the flow is largely laminar and tends to separate easily on the suction surface of the blade, and this laminar separation in particular leads to significant degradation of engine performance due to large re-circulation zones. Therefore, a better understanding of low-Reynolds number flow transition and separation is very critical for an effective design of LPT blade, and in exploring various possibilities for implementing flow control techniques, passive or active, to prevent or delay the flow separation in the low-pressure turbine. The objective of the present study is to understand the three-dimensional flow separation that occurs inside an LPT cascade at very low Reynolds numbers, and a high-order accurate numerical solution procedure is used to attain the same. A multi-block, periodic, structured grid generated by the grid generation software, GRIDPRO, is used to represent the flow domain. A MPI-based higher-order, parallel, chimera version of the FDL3DI flow solver, developed by the Air Force Research Laboratory at Wright Patterson Air Force Base, is extended for the present turbomachinery application. A sixth-order accurate compact-difference scheme is used for the spatial discretization, along with second-order accurate temporal discretization. Up to tenth-order filtering has been applied to minimize the numerical oscillations, and maintain numerical stability. Simulations have been performed for Reynolds numbers (based on inlet velocity and axial chord) 10,000 and 25,000. The effect of these low-Reynolds numbers on the flow physics for a low-pressure turbine cascade has been studied in detail. At Re = 10,000, the flow undergoes more separation than at Re = 25,000 as expected and the separation remains significant over the entire blade for both the Reynolds number. The location of the onset of separation matches with an available LES simulation and with the available experimental data. In addition to the above simulations, another study was carried out to understand the effect of two different sets of inflow/outflow boundary conditions on the flow solution. The two sets of boundary conditions include static inflow with extrapolated outflow (BC1), and dynamic inflow (BC2) that accounts for upstream influence in the subsonic flow. The computed Cp distribution for the LPT flow shows good agreement with the available experimental data. Application of BC2 boundary condition predicted a bounded region of separation, while BC1 boundary condition predicted significant separation over the entire blade of an LPT.
Download or read book Large eddy Simulation of Flow Through a Low Pressure Turbine Cascade written by Shankar Venkatasubramanian and published by . This book was released on 2001 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High order Accurate Solution for Flow Through a Turbine Linear Cascade written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Low-pressure turbines (LPT) in aircraft engines undergo tremendous losses at cruise conditions. The flow Reynolds number at cruise is lower than the take-off Reynolds number by a factor of almost two. At low Reynolds numbers, the flow is largely laminar, and tends to separate easily on the suction surface of the turbine blade when an adverse pressure gradient is encountered. Therefore, accurate prediction of flow separation is crucial for an effective design of LPT blade; and is achieved in the present work using a high-order accurate numerical solution procedure. The three-dimensional, unsteady, full Navier-Stokes equations are solved to analyze the flow. A MPI-based higher-order, parallel, chimera version of the FDL3DI flow solver, is extended for use with this turbomachinery application. A sixth-order accurate compact-difference scheme is used for the spatial discretization, along with second-order accurate temporal discretization. Tenth-order filtering is used to minimize the numerical oscillations in the flow solution and maintain numerical stability. The objective of the present study is to show the ability of higher-order accurate compact-difference scheme to predict the flow separation that occurs inside an LPT cascade at Re C = 25,000 (based on axial chord and inlet velocity). A new set of subsonic inflow/outflow boundary conditions that account for upstream influence (BC2) are derived by specifying stagnation quantities at the inlet, and a static quantity at the exit of the flow domain, and maintaining the inflow angle constant. For inflow/outflow boundary conditions that do not account for upstream influence, fixed inflow with extrapolated outflow (BC1) has been utilized. The effect of the two different sets of inflow/outflow boundary conditions on the flow solution is studied, for second-order, fourth-order and sixth-order accurate schemes. The computed Cp distribution for the LPT flow shows good agreement with the existing experimental data. The location of the onset of separation matches with an available LES simulation result and with the available experimental data. The performance of high-order compact difference schemes has been assessed via simulation of laminar flow over a circular cylinder at Re D = 250 (based on free-stream velocity and cylinder diameter). The sixth-order accurate compact difference scheme with tenth-order filtering on a coarser mesh preserves the vortex structure better than possible with the second-order accurate scheme on a finer mesh. This demonstrates the efficiency of the higher-order accurate compact difference scheme.
Download or read book Direct Numerical Simulations of the Unsteady Secondary Flow in the Near wall Region of a Linear Low Pressure Turbine Cascade written by Denis Koschichow and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proceedings of the ASME Joint U S European Fluids Engineering Conference written by and published by . This book was released on 2006 with total page 950 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proceedings of the ASME Fluids Engineering Division Summer Conference 2006 written by American Society of Mechanical Engineers. Fluids Engineering Division and published by . This book was released on 2006 with total page 944 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Simulations of Turbine Cooling Flows Using a Multiblock multigrid Scheme written by Erlendur Steinthorsson and published by . This book was released on 1996 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NASA SP written by and published by . This book was released on 1992 with total page 654 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Download or read book Development of an Explicit Multiblock multigrid Flow Solver for Viscous Flows in Complex Geometries written by Erlendur Steinthorsson and published by . This book was released on 1993 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Three Dimensional Flow in the Root Region of Wind Turbine Rotors written by Galih Bangga and published by kassel university press GmbH. This book was released on 2018-06-20 with total page 183 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the state of the art in the analyses of three-dimensional flow over rotating wind turbine blades. Systematic studies for wind turbine rotors with different sizes were carried out numerically employing three different simulation approaches, namely the Euler, URANS and DDES methods. The main mechanisms of the lift augmentation in the blade inboard region are described in detail. The physical relations between the inviscid and viscous effects are presented and evaluated, emphasizing the influence of the flow curvature on the resulting pressure distributions. Detailed studies concerning the lift augmentation for large wind turbine rotors are considered as thick inboard airfoils characterized by massive separation are desired to stronger contribute to power production. Special attention is given to the analyses of wind turbine loads and flow field that can be helpful for the interpretation of the occurring physical phenomena. The book is aimed at students, researchers, engineers and physicists dealing with wind engineering problems, but also for a wider audience involved in flow computations.
Download or read book Aeronautical Engineering written by and published by . This book was released on 1991 with total page 538 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Numerical Investigation of Transitional Flow Through a Low pressure Turbine Cascade written by Donald P. Rizzetta and published by . This book was released on 2003 with total page 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:
