CFD Analysis of Compressible Flow Across a Complex Geometry Venturi

2007 ◽  
Vol 129 (9) ◽  
pp. 1193-1202 ◽  
Author(s):  
Diego A. Arias ◽  
Timothy A. Shedd
Keyword(s):  
Compressible Flow ◽  
Discharge Coefficient ◽  
Static Pressure ◽  
Complex Geometry ◽  
Three Dimensional ◽  
Turbulent Model ◽  
Cfd Simulations ◽  
Pressure Losses ◽  
Computational Fluid Dynamics Cfd ◽  
Fuel Tube

A commercial computational fluid dynamics (CFD) package was used to develop a three-dimensional, fully turbulent model of the compressible flow across a complex-geometry venturi, such as those typically found in small engine carburetors. The results of the CFD simulations were used to understand the effect of the different obstacles in the flow on the overall discharge coefficient and the static pressure at the tip of the fuel tube. It was found that the obstacles located at the converging nozzle of the venturi do not cause significant pressure losses, while those obstacles that create wakes in the flow, such as the fuel tube and throttle plate, are responsible for most of the pressure losses. This result indicated that an overall discharge coefficient can be used to correct the mass flow rate, while a localized correction factor can be determined from three-dimensional CFD simulations in order to estimate the static pressure at locations of interest within complex venturis.

Computational Fluid Dynamic Analysis of Compressible Flow across a Complex Geometry Carburettor Venturi

2018 ◽  
Vol 6 (7) ◽  
pp. 83
Author(s):  
Arvind .T ◽  
Swaminathan M. R
Keyword(s):  
Compressible Flow ◽  
Static Pressure ◽  
Cfd Simulation ◽  
Complex Geometry ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Valve Design ◽  
Computational Fluid Dynamic Analysis ◽  
Throttle Valve ◽  
Fuel Tube

A commercial computational fluid dynamics package could be used to develop a three dimensional, fully turbulent model of the compressible flow across a complex geometry venturi, such as those found in small engine carburettors. The results of the CFD simulation can be used to understand the effect of the different obstacles in the flow on the mass flow rate and the static pressure at the tip of the fuel tube. This would be helpful to analyze the pressure loss in the throat area. Analysis would be performed to study airflow across carburettor venturi by locating fuel tube at the diverging nozzle of the venturi and for various positions of throttle valve in the present paper, fuel tube and throttle plate would be modelled and analyze in order to have better understanding of the flow in complex venturi. The results of this study necessitate for modification throttle valve design. The carburettor body is remodelled with two throttle bodies replacing conventional throttle. Analysis has been performed to study flow field with modified design and results have been discussed.

scholarly journals Comparison of pressure reconstruction approaches based on measured and simulated velocity fields

2017 ◽  
Vol 3 (2) ◽  
pp. 309-312
Author(s):  
Samuel Manthey ◽  
Samuel Voß ◽  
Christoph Roloff ◽  
Daniel Stucht ◽  
Dominique Thévenin ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Reconstruction Algorithm ◽  
Velocity Fields ◽  
Cfd Simulations ◽  
Pressure Poisson Equation ◽  
Pressure Losses ◽  
Velocity Information ◽  
Computational Fluid Dynamics Cfd ◽  
Diagnostic Indicator

AbstractThe pressure drop over a pathological vessel section can be used as an important diagnostic indicator. However, it cannot be measured non-invasively. Multiple approaches for pressure reconstruction based on velocity information are available. Regarding in-vivo data introducing uncertainty these approaches may not be robust and therefore validation is required. Within this study, three independent methods to calculate pressure losses from velocity fields were implemented and compared: A three dimensional and a one dimensional method based on the Pressure Poisson Equation (PPE) as well as an approach based on the work-energy equation for incompressible fluids (WERP). In order to evaluate the different approaches, phantoms from pure Computational Fluid Dynamics (CFD) simulations and in-vivo PC-MRI measurements were used. The comparison of all three methods reveals a good agreement with respect to the CFD pressure solutions for simple geometries. However, for more complex geometries all approaches lose accuracy. Hence, this study demonstrates the need for a careful selection of an appropriate pressure reconstruction algorithm.

scholarly journals Cold Flow Computations for the Diffuser-Combustor Section of an Industrial Gas Turbine

1996 ◽  
Author(s):  
Dadong Zhou ◽  
Ting Wang ◽  
William R. Ryan
Keyword(s):  
Gas Turbine ◽  
Total Pressure ◽  
Reverse Flow ◽  
Three Dimensional ◽  
Complex Flow ◽  
Pressure Losses ◽  
Structured Grid ◽  
Computational Fluid Dynamics Cfd ◽  
Enhance Efficiency ◽  
Industrial Gas Turbine

In the first part of a multipart project to analyze and optimize the complex three-dimensional diffuser-combustor section of a highly advanced industrial gas turbine under development, a computational fluid dynamics (CFD) analysts has been conducted. The commercial FEA code I-DEAS was used to complete the three-dimensional solid modeling and the structured grid generation. The flow calculation was conducted using the commercial CFD code PHOENICS. The multiblock method was employed to enhance computational capabilities. The mechanisms of the total pressure losses and possible ways to enhance efficiency by reducing the total pressure losses were examined. Mechanisms that contribute to the nonuniform velocity distribution of flow entering the combustor were also identified. The CFD results were informative and provided insight to the complex flow patterns in the reverse flow dump diffuser, however, the results are qualitative and are useful primarily as guidelines for optimization as opposed to firm design configuration selections.

Transient CFD Visualization of Fossil Fuel Combustion Simulations

2003 ◽  
Author(s):  
Brian Dotson ◽  
Kent Eshenberg ◽  
Chris Guenther ◽  
Thomas O’Brien
Keyword(s):  
Power Plants ◽  
High Efficiency ◽  
Cfd Simulation ◽  
Low Cost ◽  
Three Dimensional ◽  
Cfd Simulations ◽  
Projection System ◽  
Computational Fluid Dynamics Cfd ◽  
High Level ◽  
Wall System

The design of high-efficiency lower-emission coal-fed power plants is facilitated by the extensive use of computational fluid dynamics (CFD) simulations. This paper describes work conducted at the National Energy Technology Laboratory (NETL) and Pittsburgh Supercomputing Center (PSC) to provide an environment for the immersive three-dimensional visualization of CFD simulation results. A low-cost high-resolution projection system has been developed in the visualization lab at NETL. This multi-wall system consists of four projection screens, three of which are tiled into four quadrants. The graphics for the multi-wall system are rendered using a cluster of eight personal computers. A high-level visualization interface named Mavis has also been developed to combine the powerful 3D modules of OpenDX with methods developed at NETL for studying multiphase CFD data. With Python, a completely new OpenDX user interface was built that extends and simplifies the features of a basic graphics library.

scholarly journals A Comparative Study on the Performance of a Horizontal Axis Ocean Current Turbine Considering Deflector and Operating Depths

2020 ◽  
Vol 12 (8) ◽  
pp. 3333
Author(s):  
Nauman Riyaz Maldar ◽  
Cheng Yee Ng ◽  
Lee Woen Ean ◽  
Elif Oguz ◽  
Ahmad Fitriadhy ◽  
...  
Keyword(s):  
Fluid Pressure ◽  
Three Dimensional ◽  
Horizontal Axis ◽  
Ocean Current ◽  
Power Coefficient ◽  
Cfd Simulations ◽  
Torque Coefficient ◽  
Computational Fluid Dynamics Cfd ◽  
Turbine Design ◽  
Current Turbine

Several different designs and prototypes of ocean current turbines have been tested over recent years. For every design test, emphasis is given to achieving an optimum power output from the flow. In this study, the performance of a Horizontal Axis Ocean Current Turbine (HAOCT) has been investigated using three-dimensional Computational Fluid Dynamics (CFD) simulations for three cases, namely, (1) a turbine without a deflector, (2) a turbine with a deflector, and (3) a turbine with a deflector operating at a higher fluid depth. The turbine design was modeled in DesignModeler software and simulations were carried out in commercial CFD software Flow-3D. The Torque Coefficient (Cm) and Power Coefficient (Cp) for the turbine have been investigated for a certain range of Tip-Speed Ratios (TSRs) in a flow velocity of 0.7 m/s. Furthermore, comparisons have been made to demonstrate the effect of the deflector on the performance of the turbine and the influence of a higher fluid pressure on the same. The results from the simulations indicate that the higher value of Cp was achieved for Case 2 as compared to the other two cases. The findings from the study indicate that the use of the deflector enhances the performance of the turbine. Furthermore, a higher fluid pressure acting on the turbine has a significant effect on its performance.

scholarly journals Application of a three-dimensional viscous transonic inverse method to NASA rotor 67

2002 ◽  
Vol 216 (3) ◽  
pp. 243-255 ◽  
Author(s):  
W. T. Tiow ◽  
M Zangeneh
Keyword(s):  
High Speed ◽  
Inverse Method ◽  
Static Pressure ◽  
Three Dimensional ◽  
Test Case ◽  
Shock Formation ◽  
Pressure Loading ◽  
Design Computation ◽  
Computational Fluid Dynamics Cfd ◽  
Blade Geometry

The development and application of a three-dimensional inverse methodology in which the blade geometry is computed on the basis of the specification of static pressure loading distribution is presented. The methodology is based on the intensive use of computational fluid dynamics (CFD) to account for three-dimensional subsonic and transonic viscous flows. In the design computation, the necessary blade changes are determined directly by the discrepancies between the target and initial values, and the calculation converges to give the final blade geometry and the corresponding steady state flow solution. The application of the method is explored using a transonic test case, NASA rotor 67. Based on observations, it is conclusive that the shock formation and its intensity in such a high-speed turbomachinery flow are well defined on the loading distributions. Pressure loading is therefore as effective a design parameter as conventional inverse design quantities such as static pressure. Hence, from an understanding of the dynamics of the flow in the fan in relation to its pressure loading distributions, simple guidelines can be developed for the inverse method in order to weaken the shock formation. A qualitative improvement in performance is achieved in the redesigned fan. The final flowfield result is confirmed by a well-established commercial CFD package.

Simulation of Spray Cooling in a Desublimer

2000 ◽  
Author(s):  
Malcolm J. Andrews ◽  
David Zwick
Keyword(s):  
Drop Size ◽  
Three Dimensional ◽  
Spray Cooling ◽  
Cfd Modeling ◽  
Lagrangian Description ◽  
Water Spray ◽  
Cfd Simulations ◽  
Computational Fluid Dynamics Cfd ◽  
Fully Coupled ◽  
Water Spray Cooling

Abstract Three-dimensional Computational Fluid Dynamics (CFD) simulations are presented for water spray cooling of a Phthalic Anhydride desublimer. The multiphase CFD modeling includes a fully coupled Eulerian/Lagrangian formulation for the carrier gas and water spray, and a quasi-steady model for the desublimation process. The use of a Lagrangian description for the spray enables a drop size distribution, but also necessitates running the simulation through the transient to obtain a steady operation result. The simulation has been used to study effect of drop size, spray dispersion and spray location/orientation.

Fast Optimisation of a Three-Dimensional Bypass System Using a New Aerodynamic Design Method

2017 ◽  
Author(s):  
F. Barbarossa ◽  
M. E. Rife ◽  
M. Carnevale ◽  
A. B. Parry ◽  
J. S. Green ◽  
...  
Keyword(s):  
Power Plants ◽  
Static Pressure ◽  
Design Method ◽  
Three Dimensional ◽  
Civil Aviation ◽  
Propulsive Efficiency ◽  
Singularity Method ◽  
Design Variables ◽  
Computational Fluid Dynamics Cfd ◽  
Bypass Ratio

The propulsive efficiency of civil aviation power plants can be effectively improved by increasing the bypass ratio. Higher bypass ratios, however, exacerbate issues of performance, stability and integrity due to the interaction between the engine pylon, the outlet guide vanes (OGV) and the fan. These issues are due to the distortion of the static pressure field at fan exit due to the presence of the pylon and its transmission through the OGV bladerow and are more pronounced the closer the components of the low pressure compression (LPC) system are. These issues make a rational and effective design of the LPC system of paramount importance for the success of very high-bypass ratio engines. At the preliminary design phase, methods that utilise computational fluid dynamics (CFD) are prohibitively expensive, particularly if they are used as part of optimisation processes involving highly three dimensional, non-axisymmetric OGV designs. An alternative method is being developed exploiting the simplicity and the accuracy of surface singularity element methods to investigate the sensitivity of the bypass system to changes in the design variables. Although the singularity method is based on simplified assumptions of inviscid, incompressible flow, it still performs remarkably well when combined with a tailored optimisation technique. This paper discusses the optimisation framework in detail, including the underlying mathematical models that describe the three-dimensional aerodynamic flowfield as well as the optimisation tools, variables and cost functions used within the optimisation process. The results show that the proposed approach can be used to explore quickly and efficiently a far wider design space than attempted so far in literature. Furthermore, the proposed method leads to non-axysymmetric cascade designs whereby every vane has the same load as the nominal vane whilst greatly reducing the static pressure distortion at fan exit.

Extent, capacity and possibilities of computational fluid dynamics as a design tool for pump intakes: a review

2018 ◽  
Vol 18 (5) ◽  
pp. 1518-1530 ◽  
Author(s):  
Jie Zhang ◽  
Tien Yee
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Three Dimensional ◽  
Design Tool ◽  
Cfd Modeling ◽  
Cfd Simulations ◽  
Pump Station ◽  
Computational Fluid Dynamics Cfd ◽  
Future Direction ◽  
Computational Resources

Abstract Flow near pump intakes is three-dimensional in nature, and is affected by many factors such as the geometry of the intake bay, uniformity of approach flow, critical submergence, placements and operation combinations of pumps and so on. In the last three decades, advancement of numerical techniques coupled with the increase in computational resources made it possible to conduct computational fluid dynamics (CFD) simulations on pump intakes. This article reviews different aspects involved in CFD modeling of pump station intakes, outlines the challenges faced by current CFD modelers, and provides an attempt to forecast future direction of CFD modeling of pump intakes.

A Hybrid Particle-Continuum Framework

2008 ◽  
Author(s):  
Matthew K. Borg ◽  
Jason M. Reese
Keyword(s):  
Three Dimensional ◽  
Computational Modelling ◽  
Numerical Code ◽  
Test Cases ◽  
Cfd Simulations ◽  
Hybrid Particle ◽  
Hybrid Framework ◽  
Computational Fluid Dynamics Cfd ◽  
Polyhedral Cells ◽  
The Individual

A new hybrid particle-continuum numerical code is currently being developed as an engineering tool for accurate and fast computational modelling of nanoflows. Molecular Dynamics (MD) and Computational Fluid Dynamics (CFD) are the components/solvers used within the particle and continuum zones respectively. In this paper the development of a two-component hybrid framework, based on domain-decomposition, is described. The main objective of the framework is to facilitate hybrid MD-CFD simulations within complex geometries, using a mesh of structured/unstructured arbitrary polyhedral cells, identical to that used in engineering CFD. This requires complex three-dimensional (3D) interfaces and overlap regions (comprising user-defined sub-regions) to be constructed between adjacent zones. The individual sub-regions serve as an appropriate means of exchanging information between components (i.e. coupling or boundary condition imposition), in 3D, during the hybrid simulation. The global domain is decomposed appropriately into MD and CFD sub-domains such that internal boundaries within the overlap regions become the external boundaries on the separate meshes, prior to commencing the hybrid simulations. The hybrid framework is implemented in OpenFOAM [1], an open source C++ CFD toolbox, using a general, case-independent approach and is parallelised. Two nanochannel test cases are investigated to show that the hybrid environment is flexible and well-suited for engineering design applications as well for the development of new hybrid codes and coupling models.

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