A Time-Parallel CFD Approach for Unsteady Combustor Flow Analysis and Design Optimization

2012 ◽  
Author(s):  
Moresh J. Wankhede ◽  
Neil W. Bressloff ◽  
Andy J. Keane
Keyword(s):  
Flow Field ◽  
Domain Decomposition ◽  
Design Optimization ◽  
Cfd Simulation ◽  
Simulation Method ◽  
Spatial Domain ◽  
Parallel Simulation ◽  
Analysis And Design ◽  
Temporal Domain ◽  
Parallel Cfd

Computational fluid dynamics (CFD) simulations to predict and visualize the reacting flow dynamics inside a combustor require fine resolution over the spatial and temporal domain, making them computationally very expensive. The traditional time-serial approach for setting up a parallel combustor CFD simulation is to divide the spatial domain between computing nodes and treat the temporal domain sequentially. However, it is well known that spatial domain decomposition techniques are not very efficient especially when the spatial dimension (or mesh count) of the problem is small and a large number of nodes are used, as the communication costs due to data parallelism becomes significant per iteration. Hence, temporal domain decomposition has some attraction for unsteady simulations, particularly on relatively coarse spatial meshes. The purpose of this study is two-fold: (i), to develop a time-parallel CFD simulation method and apply it to solve the transient reactive flow-field in a combustor using an unsteady Reynolds-averaged Navier Stokes (URANS) formulation in the commercial CFD code FLUENT™ and (ii) to investigate its benefits relative to a time-serial approach and its potential use for combustor design optimization. The results show that the time-parallel simulation method correctly captures the unsteady combustor flow evolution but, with the applied time-parallel formulation, a clear speed-up advantage, in terms of wall-clock time, is not obtained relative to the time-serial approach. However, it is clear that the time-parallel simulation method provides multiple stages of transient combustor flow-field solution data whilst converging towards a final converged state. The availability of this resulting data could be used to seed multiple levels of fidelity within the framework of a multi-fidelity co-Kriging based design optimization strategy. Also, only a single simulation would need to be setup from which multiple fidelities are available.

Research on CFD Simulation of the Cement Slurry Mixer

2012 ◽  
Vol 621 ◽  
pp. 196-199
Author(s):  
Shui Ping LI ◽  
Ya Li Yuan ◽  
Lu Gang Shi
Keyword(s):  
Flow Field ◽  
High Performance ◽  
Cfd Simulation ◽  
Structural Parameters ◽  
Internal Flow ◽  
Simulation Method ◽  
Cement Slurry ◽  
Fluid Machinery ◽  
Computational Fluid Dynamics Cfd ◽  
Machinery Design

Numerical simulation method of the internal flow field of fluid machinery has become an important technology in the study of fluid machinery design. In order to obtain a high-performance cement slurry mixer, computational fluid dynamics (CFD) techniques are used to simulate the flow field in the mixer, and the simulation results are studied. According to the analysis results, the structural parameters of the mixer are modified. The results show the mixer under the revised parameters meet the design requirements well. So CFD analysis method can shorten design period and provide valuable theoretical guidance for the design of fluid machinery.

scholarly journals An Arbitrary Hybrid Turbulence Modeling Approach for Efficient and Accurate Automotive Aerodynamic Analysis and Design Optimization

Fluids ◽  
2021 ◽  
Vol 6 (11) ◽  
pp. 407
Author(s):  
Saule Maulenkul ◽  
Kaiyrbek Yerzhanov ◽  
Azamat Kabidollayev ◽  
Bagdaulet Kamalov ◽  
Sagidolla Batay ◽  
...  
Keyword(s):  
Flow Field ◽  
Design Optimization ◽  
Automotive Industry ◽  
Turbulence Modeling ◽  
Turbulence Models ◽  
Analysis And Design ◽  
Eddy Simulation ◽  
Gradient Based ◽  
Automotive Aerodynamics ◽  
Single Flow

The demand in solving complex turbulent fluid flows has been growing rapidly in the automotive industry for the last decade as engineers strive to design better vehicles to improve drag coefficients, noise levels and drivability. This paper presents the implementation of an arbitrary hybrid turbulence modeling (AHTM) approach in OpenFOAM for the efficient simulation of common automotive aerodynamics with unsteady turbulent separated flows such as the Kelvin–Helmholtz effect, which can also be used as an efficient part of aerodynamic design optimization (ADO) tools. This AHTM approach is based on the concept of Very Large Eddy Simulation (VLES), which can arbitrarily combine RANS, URANS, LES and DNS turbulence models in a single flow field depending on the local mesh refinement. As a result, the design engineer can take advantage of this unique and highly flexible approach to tailor his grid according to his design and resolution requirements in different areas of the flow field over the car body without sacrificing accuracy and efficiency at the same time. This paper presents the details of the implementation and careful validation of the AHTM method using the standard benchmark case of the Ahmed body, in comparison with some other existing models, such as RANS, URANS, DES and LES, which shows VLES to be the most accurate among the five examined. Furthermore, the results of this study demonstrate that the AHTM approach has the flexibility, efficiency and accuracy to be integrated with ADO tools for engineering design in the automotive industry. The approach can also be used for the detailed study of highly complex turbulent phenomena such as the Kelvin–Helmholtz instability commonly found in automotive aerodynamics. Currently, the AHTM implementation is being integrated with the DAFoam for gradient-based multi-point ADO using an efficient adjoint solver based on a Sparse Nonlinear optimizer (SNOPT).

Optimze the Structure of Impeller for Stirred Bioreactor

2013 ◽  
Vol 694-697 ◽  
pp. 148-153 ◽  
Author(s):  
Li Kuan Zhu ◽  
Bo Yan Song ◽  
Zhen Long Wang ◽  
Yu Kui Wang
Keyword(s):  
Fluid Dynamics ◽  
Flow Field ◽  
Shear Force ◽  
Large Scale ◽  
Cfd Simulation ◽  
Simulation Method ◽  
Stirred Bioreactor ◽  
Anticlockwise Rotation ◽  
Computational Fluid Dynamics Cfd ◽  
Large Scale Culture

This paper mainly makes comparative analysis on four main types of blade in stirred bioreactor by Computational Fluid Dynamics(CFD) simulation. Firstly we establish simulation method suited for stirred bioreactor, then simulate the velocity and shear force of flow field in the bioreactor. No matter from flow field mixing or shear force aspect, Elephant Ear blades is the most suitable for cell large scale culture. At last, it optimizes the installation method and angle of Elephant Ear blades. It concludes that anticlockwise rotation and 45°installation angle is the optimum.

Study on the Flow Characteristics of the Monolithic Muffler in Train Air Conditioning Duct

2012 ◽  
Vol 462 ◽  
pp. 300-306
Author(s):  
Xu Quan Li ◽  
Dong Dong Dong ◽  
Min Jie Gu ◽  
Gang Wang ◽  
Song Tao Hu
Keyword(s):  
Flow Field ◽  
Pressure Loss ◽  
Air Conditioning ◽  
Cfd Simulation ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Simulation Method ◽  
Calculation Model ◽  
Simulation Calculation ◽  
Performance Research

After installing the monolithic muffler in the train air duct, noise is reduced, but meanwhile also increased the air duct resistance. In this paper, a monolithic muffler simulation calculation model is introduced in this paper. The pressure loss and internal flow field of the muffler are obtained by. CFD simulation. Experimental results validate the simulation method. It provides a basis for the silencer performance research of muffler.

scholarly journals Aerodynamic Simulation of Helicopter Based on Polyhedron Nested Grid Technology

2020 ◽  
Vol 10 (22) ◽  
pp. 8304
Author(s):  
Chenglong Zhou ◽  
Ming Chen
Keyword(s):  
Flow Field ◽  
Cfd Simulation ◽  
Simulation Method ◽  
Test Results ◽  
Forward Flight ◽  
Time Stepping ◽  
Coaxial Rotor ◽  
Dual Time Stepping ◽  
Computational Fluid Dynamics Cfd ◽  
Nested Grid

In this paper, a computational fluid dynamics (CFD) simulation method based on the polyhedral nested grid is developed. By comparing the simulation and test results of the hovering flow field of the Caradonna–Tung rotor, the forward flight flow field of the AH-1G rotor, the interference flow field of the Robin rotor/fuselage, and the hovering and forward flight flow field of a coaxial rotor, it is proven that the method proposed in this paper can achieve high calculation accuracy under various working conditions. The dual time-stepping method is used for the transient simulation, and the Spalart–Allmaras (S-A) turbulence model, which is widely used in aviation, is adopted in the simulation.

Aspect and space

2017 ◽  
Author(s):  
Lucas Champollion
Keyword(s):  
Spatial Domain ◽  
The Other ◽  
Alternative View ◽  
Temporal Domain ◽  
Spatial Aspect ◽  
Temporal Aspect ◽  
The Way

This chapter models the relation between temporal aspect (run for an hour vs. *run all the way to the store for an hour) and spatial aspect (meander for a mile vs. *end for a mile) previously discussed by Gawron (2009). The chapter shows that for-adverbials impose analogous conditions on the spatial domain and on the temporal domain, and that an event may satisfy stratified reference with respect to one of the domains without satisfying it with respect to the other one as well. This provides the means to extend the telic-atelic opposition to the spatial domain. The chapter argues in some detail that stratified reference is in this respect empirically superior to an alternative view of telicity based on divisive reference (Krifka 1998).

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