Numerical Investigation of Worn Labyrinth Seals

2006 ◽  
Author(s):  
Hasham H. Chougule ◽  
Douglas Ramerth ◽  
Dhinagaran Ramchandran ◽  
Ramnath Kandala
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Numerical Investigation ◽  
Flow Characteristics ◽  
Honeycomb Structure ◽  
Labyrinth Seals ◽  
Grid Interface ◽  
Wide Range ◽  
Additional Challenge ◽  
Computational Fluid Dynamics Cfd

The objective of this study was to develop a Computational Fluid Dynamics (CFD) based methodology to obtain the flow characteristics of worn and unworn labyrinth seals which will be applicable over a wide range of seal geometries. In this paper, we present a process to analyze worn and unworn seals with honeycomb lands using the CFX suite of software. Honeycomb structure poses an additional challenge due to disparate length scales. This was addressed by using separate meshes for the honeycomb and the seal tooth and by connecting them with a generalized grid interface in CFX. The challenges involved in modeling worn seals and an approach for quality meshing of the same was discussed. Comparisons were made with the test data from seals with unworn honeycomb lands. The leakages for the worn seals were also analyzed.

CFD Leakage Predictions of Unworn and Worn Labyrinth Seals With and Without Tooth Axial Offset

2017 ◽  
Author(s):  
Hasham H. Chougule ◽  
Alexander Mirzamoghadam
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Numerical Modeling ◽  
Steady State ◽  
Flow Field ◽  
Labyrinth Seals ◽  
Small Clearance ◽  
Total Leakage ◽  
Computational Fluid Dynamics Cfd ◽  
Flow Deflection

The objective of this study is to develop a Computational Fluid Dynamics (CFD) based methodology for analyzing and predicting leakage of worn or rub-intended labyrinth seals during operation. The simulations include intended tooth axial offset and numerical modeling of the flow field. The purpose is to predict total leakage through the seal when an axial tooth offset is provided after the intended/unintended rub. Results indicate that as expected, the leakage for the in-line worn land case (i.e. tooth under rub) is higher compared to unworn. Furthermore, the intended rotor/teeth forward axial offset/shift with respect to the rubbed land reduces the seal leakage. The overall leakage of a rubbed seal with axial tooth offset is observed to be considerably reduced, and it can become even less than a small clearance seal designed not to rub. The reduced leakage during steady state is due to a targeted smaller running gap because of tooth offset under the intended/worn land groove shape, higher blockages, higher turbulence and flow deflection as compared to worn seal model without axial tooth offset.

Computational Fluid Dynamics (CFD) Study of the 4th Generation Prototype of a Continuous Flow Ventricular Assist Device (VAD)

2004 ◽  
Vol 126 (2) ◽  
pp. 180-187 ◽  
Author(s):  
Xinwei Song ◽  
Houston G. Wood ◽  
Don Olsen
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Blood Flow ◽  
Ventricular Assist Device ◽  
Continuous Flow ◽  
Surrounding Tissue ◽  
Assist Device ◽  
Ventricular Assist ◽  
Wide Range ◽  
Computational Fluid Dynamics Cfd

The continuous flow ventricular assist device (VAD) is a miniature centrifugal pump, fully suspended by magnetic bearings, which is being developed for implantation in humans. The CF4 model is the first actual prototype of the final design product. The overall performances of blood flow in CF4 have been simulated using computational fluid dynamics (CFD) software: CFX, which is commercially available from ANSYS Inc. The flow regions modeled in CF4 include the inlet elbow, the five-blade impeller, the clearance gap below the impeller, and the exit volute. According to different needs from patients, a wide range of flow rates and revolutions per minute (RPM) have been studied. The flow rate-pressure curves are given. The streamlines in the flow field are drawn to detect stagnation points and vortices that could lead to thrombosis. The stress is calculated in the fluid field to estimate potential hemolysis. The stress is elevated to the decreased size of the blood flow paths through the smaller pump, but is still within the safe range. The thermal study on the pump, the blood and the surrounding tissue shows the temperature rise due to magnetoelectric heat sources and thermal dissipation is insignificant. CFD simulation proved valuable to demonstrate and to improve the performance of fluid flow in the design of a small size pump.

CFD Modelling of Multiphase Flows: An Overview

2003 ◽  
Author(s):  
Rajnish K. Calay ◽  
Arne E. Holdo
Keyword(s):  
Fluid Dynamics ◽  
Mass Transfer ◽  
Computational Fluid Dynamics ◽  
Numerical Modeling ◽  
Mathematical Models ◽  
Cfd Modelling ◽  
Two Phase ◽  
Wide Range ◽  
Computational Fluid Dynamics Cfd ◽  
Numerical Modeling Of Flows

The Computational Fluid Dynamics (CFD) is now increasingly being used for modeling industrial flows, i.e. flows which are multiphase and turbulent. Numerical modeling of flows where momentum, heat and mass transfer occurs at the interface presents various difficulties due to the wide range of mechanisms and flow scenarios present. This paper attempts to provide a summary of available mathematical models and techniques for two-phase flows. Some comments are also made on the models available in the commercially available codes.

scholarly journals Analysis of a Converging, Annular, Isothermal Melt Blowing Jet Using Computational Fluid Dynamics

2005 ◽  
Vol os-14 (3) ◽  
pp. 1558925005os-14
Author(s):  
Eric M. Moore ◽  
Dimitrios V. Papavassiliou ◽  
Robert L. Shambaugh
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Kinetic Energy ◽  
Near Field ◽  
Flow Characteristics ◽  
Sectional Area ◽  
Melt Blowing ◽  
Mean Velocity ◽  
Cross Sectional ◽  
Computational Fluid Dynamics Cfd

An unconventional melt blowing die was analyzed using computational fluid dynamics (CFD). This die has an annular configuration wherein the jet inlet is tapered (the cross-sectional area decreases) as the air approaches the die face. It was found that the flow characteristics of this die are different from conventional slot and annular dies. In particular, for the tapered die the near-field normalized turbulent kinetic energy was found to be lower at shallow die angles. Also, it was found that the peak mean velocity behavior was intermediate between that of conventional annular and slot dies. The centerline turbulence profiles were found to be qualitatively similar to those of annular dies; quantitatively, higher values were present for tapered dies.

Experimental and Numerical Investigation of a Centrifugal Nozzle

2007 ◽  
Author(s):  
Jason Smith ◽  
Robert N. Eli
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Particulate Matter ◽  
Laboratory Experiment ◽  
Numerical Investigation ◽  
Industrial Applications ◽  
Fluid Mixing ◽  
Cfd Models ◽  
Computational Fluid Dynamics Cfd

This paper reports on a laboratory experiment conducted more than 30 years ago (Eli, 1974, unpublished), and recent Computational Fluid Dynamics (CFD) investigations, focusing on the properties of a plane tangential jet produced by an apparatus called a “centrifugal nozzle.” The authors believe that the centrifugal nozzle has potential industrial applications in several areas related to fluid mixing and particulate matter suspension in mixing tanks. It is also believed that this experiment, or one similar, may provide data useful for benchmarking CFD models.

Characterization of Single-Phase Flow Hydrodynamics in Berty Reactor using Computational Fluid Dynamics (CFD)

2021 ◽  
Author(s):  
Khunnawat Ountaksinkul ◽  
Sirada Sripinun ◽  
Panut Bumphenkiattikul ◽  
Surapon Bubphacharoen ◽  
Arthit Vongachariya ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Single Phase ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Kinetic Studies ◽  
Stirred Tank Reactors ◽  
Computational Fluid Dynamics Cfd ◽  
Continuous Stirred Tank

This work studies the flow characteristics in the Berty reactor, a gradientless reactor for kinetic studies, using three-dimensional (3D) computational fluid dynamics (CFD), and the non-ideal continuous stirred tank reactors...

scholarly journals The Effects of the Presence of a Kitchen House on the Wind Flow Surrounding a Low-Rise Building

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6243
Author(s):  
Siti Noratikah Che Deraman ◽  
Saddam Hussein Abo Sabah ◽  
Shaharudin Shah Zaini ◽  
Taksiah A. Majid ◽  
Amin Al-Fakih
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Pattern ◽  
Air Flow ◽  
Flow Characteristics ◽  
Wind Flow ◽  
Cfd Simulations ◽  
The Core ◽  
Computational Fluid Dynamics Cfd ◽  
Gap Height

Most Malaysian rural houses are categorized as non-engineered buildings and vulnerable to damage during events such as windstorms due to the fact that these houses lack engineering considerations. These houses are characterized by having an attached kitchen house, and many of these houses were previously damaged by thunderstorms. The current research investigated the air flow characteristics changes surrounding these houses as a result of the presence of the kitchen. The roof pitch, position, gap height, and overhang were investigated using computational fluid dynamics (CFD) simulations. The results showed that the kitchen position at the center resulted in a slight increase in the suction on the ridge of the roof; however, it significantly altered the flow pattern in the windward and leeward directions. The results also showed that the roof overhang, roof pitch, and kitchen position contributed severely to the damage of the rural house. Moreover, the highest suction occurred at the roof ridge when the kitchen was located at the center of the rural house (Cp = −2.28). Therefore, the authors believe that it is more advantageous to have a kitchen connected to the core as it reduces the pressure on the roof of the core during thunderstorm events.

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