Performance analysis of reciprocating compressors through computational fluid dynamics

2008 ◽  
Vol 222 (4) ◽  
pp. 183-192 ◽  
Author(s):  
E L L Pereira ◽  
C J Deschamps ◽  
F A Ribas
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Numerical Analysis ◽  
Performance Analysis ◽  
Flow Field ◽  
Three Dimensional ◽  
Time Dependent ◽  
Valve Dynamics ◽  
Dependent Flow

An experimentally validated numerical analysis of reciprocating refrigeration compressors is presented. The finite-volume methodology is adopted to solve the flow field and a one-degree-of-freedom model is used to describe the valve dynamics. The variation of the computation domain, associated with the valve and piston displacements, is taken into account and the time-dependent flow field and the valve dynamics are coupled and solved simultaneously. The three-dimensional formulation considered in the analysis allowed the simulation of actual suction and discharge muffler geometries. Numerical results were validated with reference to experimental data for valve displacement and pressure in the suction and compression chambers obtained in a calorimeter facility. A study was carried out to identify the contributions of mufflers and valves to the compressor thermodynamic losses.

Numerical Analysis on Internal Flow Field in Stator of a Torque Converter

2011 ◽  
Vol 120 ◽  
pp. 587-590
Author(s):  
Yue Liu
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Numerical Analysis ◽  
Flow Field ◽  
Internal Flow ◽  
Torque Converter ◽  
Field Characteristic

The internal flow field in stator of a torque converter was simulated. Based on the mixing-plane technology, using the method of CFD(Computational Fluid Dynamics) simulated the stator flow field. The flow field characteristic, the distribution of velocity and pressure in the stator were analyzed. The external performance of the torque converter was also calculated, and the results were compared with the experimental data. It was proved that the calculated results showed agreement with the experiment accurately.

Numerical Analysis of the LCS 2 airwake to understand potential interactions during helipcopter operations

2015 ◽  
Author(s):  
Brent S. Paul
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Numerical Analysis ◽  
Flow Field ◽  
Ship Design ◽  
It Impacts ◽  
Flight Envelope ◽  
Computational Fluid Dynamics Cfd ◽  
Potential Interactions ◽  
Flight Deck

The successful integration of aviation capabilities aboard ships is a complex endeavor that must balance ship design with the flight envelope of the helicopter. This can be particularly important when considering air wakes and other flow around the superstructure as it impacts the flight deck. This flow can generate unsteady structures that may interfere with safe helicopter operations. Computational fluid dynamics (CFD) is commonly used to characterize the flow field and assess potential impacts to the flight envelope, which can be used to help define an operating envelope for helicopter operations.

scholarly journals Assessment of the Flow Field in the HeartMate 3 Using Three-Dimensional Particle Tracking Velocimetry and Comparison to Computational Fluid Dynamics

ASAIO Journal ◽  
2020 ◽  
Vol 66 (2) ◽  
pp. 173-182 ◽  
Author(s):  
Bente Thamsen ◽  
Utku Gülan ◽  
Lena Wiegmann ◽  
Christian Loosli ◽  
Marianne Schmid Daners ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Field ◽  
Particle Tracking ◽  
Particle Tracking Velocimetry ◽  
Three Dimensional

scholarly journals NUMERICAL ANALYSIS OF THE IMPACT OF SIDESLIP ANGLE ON LOAD OF THE GYROCOPTER STABILIZERS

Aviation ◽  
2020 ◽  
Vol 23 (4) ◽  
pp. 114-122
Author(s):  
Zbigniew Czyż ◽  
Paweł Karpiński
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Numerical Analysis ◽  
Angle Of Attack ◽  
Three Dimensional ◽  
Numerical Calculations ◽  
Slip Angle ◽  
Sideslip Angle ◽  
Ansys Fluent ◽  
The Impact

The paper presents some of the works related to the project of modern gyrocopter construction with the possibility of a short start, known as "jump-start". It also presents a methodology related to numerical calculations using Computational Fluid Dynamics based on ANSYS Fluent three-dimensional solver. The purpose of the work was to calculate the forces and aerodynamic moments acting on the gyrocopter stabilizers. The calculations were carried out for a range of angle of attack α from –20° to +25° and for a sideslip angle β from 0° to 20°. Based on the calculations carried out, analysis of the impact of the slip angle on the load on the stabilizers has been made.

Laminar Fluid Flow in a Planar 90 Degree Bifurcation With and Without a Protruding Branching Duct

1996 ◽  
Vol 118 (1) ◽  
pp. 81-84 ◽  
Author(s):  
T. G. Travers ◽  
W. M. Worek
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Fluid Flow ◽  
Velocity Field ◽  
Pressure Drop ◽  
Laminar Flow ◽  
Flow Field ◽  
Numerical Study ◽  
Main Duct

The laminar flow field in a planar, ninety degree bifurcation is examined. This numerical study uses the computational-fluid-dynamics software Fluent Version 4.11. First, the velocity field in a bifurcation without a protruding branching duct is modeled, and the results are successfully compared to experimental data. Next, the flow field is studied in bifurcations that have branching ducts that protrude into the main duct. The velocity field and pressure drop are documented, and are found to be strongly influenced by the extent of the branching duct protrusion.

Comparisons of Magnetic Resonance Imaging Velocimetry With Computational Fluid Dynamics

1997 ◽  
Vol 119 (1) ◽  
pp. 103-109 ◽  
Author(s):  
B. Newling ◽  
S. J. Gibbs ◽  
J. A. Derbyshire ◽  
D. Xing ◽  
L. D. Hall ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Magnetic Resonance ◽  
Flow Field ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Resonance Imaging ◽  
Pipe System

The flow of Newtonian liquids through a pipe system comprising of a series of abrupt expansions and contractions has been studied using several magnetic resonance imaging (MRI) techniques, and also by computational fluid dynamics. Agreement between those results validates the assumptions inherent to the computational calculation and gives confidence to extend the work to more complex geometries and more complex fluids, wherein the advantages of MRI (utility in opaque fluids and noninvasiveness) are unique. The fluid in the expansion-contraction system exhibits a broad distribution of velocities and, therefore, presents peculiar challenges to the measurement technique. The MRI protocols employed were a two-dimensional tagging technique, for rapid flow field visualisation, and three-dimensional echo-planar and gradient-echo techniques, for flow field quantification (velocimetry). The Computational work was performed using the FIDAP package to solve the Navier-Stokes equations. The particular choice of parameters for both MRI and computational fluid dynamics, which affect the results and their agreement, have been addressed.

scholarly journals Assessment of Computational Fluid Dynamics Capabilities for the Prediction of Three-Dimensional Separated Flows: The DELFT 372 Catamaran in Static Drift Conditions

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
R. Broglia ◽  
S. Zaghi ◽  
E. F. Campana ◽  
T. Dogan ◽  
H. Sadat-Hosseini ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Field ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Separated Flow ◽  
Lateral Force ◽  
Separated Flows ◽  
Overlapping Grids ◽  
Wave Induced

In this paper, capabilities of state-of-the-art computational fluid dynamics (CFD) tools in the prediction of the flow-field around a multihull catamaran advancing in straight ahead motion at nonzero drift angles are investigated. CFD estimations have been provided by three research institutes by using their in-house codes: CNR-INM using Xnavis, IIHR using CFDShip-Iowa, and CNRS/ECN using ISIS. These allowed an in-depth comparison between different methodologies, such as structured overlapping grids versus unstructured grid, different turbulence models and detached eddy simulations (DES) approaches, and level-set (LS) versus volume of fluid (VoF). The activities were pursued within the NATO AVT-183 group “reliable prediction of separated flow onset and progression for air and sea vehicles,” aimed at the assessment of CFD predictions of large three-dimensional separated flows. Comparison between estimations is provided for both integral and local quantities, and for wave-induced vortices. Validation is reported by comparison against the available experimental fluid dynamics (EFD) data. Generally, all the simulations are able to capture the main features of the flow field; grid resolution effects are dominant in the onset phase of coherent structures and turbulence model affects the dynamic of the vortices. Hydrodynamic loads are in agreement between the submissions with standard deviation of about 3.5% for the resistance prediction and about 7% for lateral force and yaw moment estimation. Wave-induced vortices are correctly captured by both LS and VoF approaches, even if some differences have been highlighted, LS showing well-defined and long life vortices.

Development and Validation of a Three-Dimensional Multiphase Flow Computational Fluid Dynamics Analysis for Journal Bearings in Steam and Heavy Duty Gas Turbines

2012 ◽  
Vol 134 (10) ◽  
Author(s):  
Stephan Uhkoetter ◽  
Stefan aus der Wiesche ◽  
Michael Kursch ◽  
Christian Beck
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Multiphase Flow ◽  
Gas Turbines ◽  
Three Dimensional ◽  
Air Entrainment ◽  
Journal Bearings ◽  
Heavy Duty ◽  
Computational Fluid Dynamics Analysis

The traditional method for hydrodynamic journal bearing analysis usually applies the lubrication theory based on the Reynolds equation and suitable empirical modifications to cover turbulence, heat transfer, and cavitation. In cases of complex bearing geometries for steam and heavy-duty gas turbines, this approach has its obvious restrictions in regard to detail flow recirculation, mixing, mass balance, and filling level phenomena. These limitations could be circumvented by applying a computational fluid dynamics (CFD) approach, resting closer to the fundamental physical laws. The present contribution reports about the state of the art of such a fully three-dimensional multiphase-flow CFD approach, including cavitation and air entrainment for high-speed turbomachinery journal bearings. It has been developed and validated using experimental data. Due to the high ambient shear rates in bearings, the multiphase-flow model for journal bearings requires substantial modifications in comparison to common two-phase flow simulations. Based on experimental data, it is found, that particular cavitation phenomena are essential for the understanding of steam and heavy-duty-type gas turbine journal bearings.

Mass Transfer Considerations in the Design of Vapor-Phase photocatalytic Reactors

1998 ◽  
Vol 3 (2) ◽  
Author(s):  
Ali Τ- Raissi ◽  
Eric D. Martin ◽  
Sivakumar Jaganathan
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Mass Transfer ◽  
Computational Fluid Dynamics ◽  
Flow Field ◽  
Vapor Phase ◽  
Flow Reactor ◽  
Scale Up ◽  
Computational Techniques ◽  
Photocatalytic Reactors

AbstractAs the bench-scale photoreactors are upscaled to progressively larger units, heat and mass transfer considerations become increasingly important. Powerful analytical and computational techniques are available to augment experimental data and aid process optimization and scale up. In this paper, the analytical and computational techniques available for the design of vapor-phase photocatalytic reactors are discussed. First, the Graetz- Nusselt-Leveque problem in annuli is analyzed and its application to the design of the photocatalytic reactors described. Then, the analytical predications are compared to experimental flow reactor data. Finally, results from a Computational Fluid Dynamics program simulating a flow field within an annular baffled photoreactor are given and discussed. These techniques are particularly useful as they simplify the design and scale-up of vapor-phase photocatalytic reactors.

Sign in / Sign up

Export Citation Format

Share Document