The Use of Hydrostatic Thrust Bearing in Flow and Temperature Measurements

1975 ◽  
Vol 97 (1) ◽  
pp. 116-120
Author(s):  
S. A. Morsi
Keyword(s):  
Temperature Sensor ◽  
Thrust Bearing ◽  
Temperature Measurements ◽  
Flow Rates ◽  
Pressure Drops ◽  
Small Pressure ◽  
Constant Resistance ◽  
And Performance ◽  
New Applications ◽  
Large Flow

This paper describes two new applications for the hydrostatic thrust bearing. The first application is the use of the bearing, when the gap is fixed, as a linear constant resistance. Several bearings have been connected together in parallel to obtain large flow rates at small pressure drops for use as a flowmeter. The second application is the use of a bearing, when modified, as a temperature sensor. Description and performance of this modified design when used as a temperature sensor are given.

Dynamic Simulation Model of a Hydraulic Valve Utilizing the Ho¨rbiger Plate Principle and Piezoactuation to Achieve High Bandwidth and Flow Performance

2008 ◽  
Author(s):  
David T. Branson ◽  
Fengcai Wang ◽  
Chris R. Bowen ◽  
Patrick S. Keogh
Keyword(s):  
High Performance ◽  
Fluid Dynamic ◽  
Dynamic Simulations ◽  
Flow Rates ◽  
Pressure Drops ◽  
Dynamic Simulation Model ◽  
High Bandwidth ◽  
Performance Research ◽  
Large Flow ◽  
Hydraulic Valve

In order to increase hydraulically actuated machine system performance, valves with high performance bandwidths and large flow rates at low pressure drops are needed. While high flow rates were previously achieved using either very large spool strokes and/or diameters that would hinder valve performance, research is underway on a valve incorporating the Ho¨rbiger plate principle. This principle utilizes multiple metering edges to allow for increased flow at specified pressure drops and using small spool displacements. The valve configuration is then directly actuated using a piezoactuator to further increase valve dynamic response. This paper examines the development of a dynamic valve model using computational fluid dynamic simulations to predict fluid inertance parameters, and combines this with models for the piezoactuator, power amplifier, supply flow, fluid squeeze forces, end stop response, and valve mechanical components. Steady state and dynamic simulations of the valve are then evaluated.

scholarly journals The benefits of planar circular mouths on suction feeding performance

2012 ◽  
Vol 9 (73) ◽  
pp. 1767-1773 ◽  
Author(s):  
Tyler Skorczewski ◽  
Angela Cheer ◽  
Peter C. Wainwright
Keyword(s):  
Prey Capture ◽  
Peak Flow ◽  
Mouth Opening ◽  
Suction Feeding ◽  
Flow Rates ◽  
Computational Fluid Dynamics Simulations ◽  
Enhance Efficiency ◽  
And Performance ◽  
Dynamics Simulations ◽  
Hydrodynamic Effects

Suction feeding is the most common form of prey capture across aquatic feeding vertebrates and many adaptations that enhance efficiency and performance are expected. Many suction feeders have mechanisms that allow the mouth to form a planar and near-circular opening that is believed to have beneficial hydrodynamic effects. We explore the effects of the flattened and circular mouth opening through computational fluid dynamics simulations that allow comparisons with other mouth profiles. Compared to mouths with lateral notches, we find that the planar mouth opening results in higher flow rates into the mouth and a region of highest flow that is positioned at the centre of the mouth aperture. Planar mouths provide not only for better total fluid flow rates through the mouth but also through the centre of the mouth near where suction feeders position their prey. Circular mouths are shown to provide the quickest capture times for spherical and elliptical prey because they expose the prey item to a large region of high flow. Planar and circular mouths result in higher flow velocities with peak flow located at the centre of the mouth opening and they maximize the capacity of the suction feeders to exert hydrodynamic forces on the prey.

Optimization of Inlet Ring Groove Arrangement for Suppression of Unstable Flow in a Centrifugal Impeller

2005 ◽  
Author(s):  
Masahiro Ishida ◽  
Daisaku Sakaguchi ◽  
Hironobu Ueki
Keyword(s):  
Flow Rate ◽  
The Other ◽  
Centrifugal Impeller ◽  
Shape Parameters ◽  
Unstable Flow ◽  
Ring Groove ◽  
Flow Rates ◽  
Small Flow ◽  
Specific Speed ◽  
Large Flow

An optimization of the inlet ring groove arrangement has been pursued in the present study for obtaining better impeller characteristics and a wider operation range at both small and large flow rates in a high specific speed type centrifugal impeller with inducer. The effects of the shape parameters with respect to the inlet ring groove on the impeller characteristic and the flow incidence were analyzed mainly based on numerical simulations, but also compared to the experimental results. At small flow rates, a significant improvement in the impeller characteristic is achieved due to reduction in the excessive-positive flow incidence by optimizing both location and width of the rear groove near the inducer tip throat. On the other hand, the impeller characteristic is improved at large flow rates by implementing the corner radius at the rear groove edge and by placing another front ring groove in the suction pipe. As a result, by the optimized configuration of the front and rear ring grooves, the unstable flow range of the test impeller can be reduced by about 50% without deterioration of the impeller characteristic even at the 125% flow rate.

Mechanically Aspirated Solar Radiation Shields: A CFD and Neural Network Design Analysis

2001 ◽  
Author(s):  
B. M. Fichera ◽  
R. L. Mahajan ◽  
T. W. Horst
Keyword(s):  
Neural Network ◽  
Solar Radiation ◽  
Temperature Sensor ◽  
Temperature Measurements ◽  
Analysis And Design ◽  
Computational Fluid Dynamics Analysis ◽  
Radiation Shields ◽  
Input Variables ◽  
The Relationship

Abstract Accurate air temperature measurements made by surface meteorological stations are demanded by climate research programs for various uses. Heating of the temperature sensor due to inadequate coupling with the environment can lead to significant errors. Therefore, accurate in-situ temperature measurements require shielding the sensor from exposure to direct and reflected solar radiation, while also allowing the sensor to be brought into contact with atmospheric air at the ambient temperature. The difficulty in designing a radiation shield for such a temperature sensor lies in satisfying these two conditions simultaneously. In this paper, we perform a computational fluid dynamics analysis of mechanically aspirated radiation shields (MARS) to study the effect of geometry, wind speed, and interplay of multiple heat transfer processes. Finally, an artificial neural network model is developed to learn the relationship between the temperature error and specified input variables. The model is then used to perform a sensitivity analysis and design optimization.

scholarly journals Study of Transmissivity of a Fracture Under Shearing

2018 ◽  
Author(s):  
Amir A. Mofakham ◽  
Goodarz Ahmadi ◽  
Matthew Stadelman ◽  
Kevin Shanley ◽  
Dustin Crandall
Keyword(s):  
Surface Roughness ◽  
Rock Fracture ◽  
Marcellus Shale ◽  
Ct Scans ◽  
Navier Stokes ◽  
Fast Method ◽  
Flow Rates ◽  
Pressure Drops ◽  
Fracture Pressure ◽  
Cubic Law

A Marcellus shale rock fracture was subjected to four shearing steps and at the end of each shearing step CT (computed tomography) scans with resolution of 26.8 μm were obtained. The CT images were used to generate full aperture maps of the fracture configuration at the end of each shearing phase. The pressure drops along the fracture were also measured for different water flow rates through the fracture. The aperture map of the fracture was used to generate the geometry of the fracture for use in numerical simulations. The water flows and pressure drops in the fracture were simulated with different computational methods that included the full Navier-Stokes simulation, Modified Local Cubic Law (MLCL), and Improved Cubic Law (ICL) methods. Full 3-D Navier-Stokes simulation is the most accurate computational approach which was done with use of the ANSYS-Fluent software for each shear step and different flow rates. The MLCL is a 2-D relatively fast method which is commonly used for prediction of transmissivity of fractures. ICL is a 1-D method proposed in this study in which the effects of surface roughness and tortuosity were included in calculation of the effective aperture height of fractures. To provide an understanding of the accuracy of each of these models their predictions were compared with each other and with the experimental data. Also, to examine the effects of resolution of CT scans and the surface roughness on prediction of fractures transmissivity, similar simulations were performed on average aperture maps. Here the fracture of the full resolution data was averaged over 10 × 10 pixels. Comparing the results of the average aperture maps with those of the full maps showed that the lower resolution of CT scans led to underestimation of the fracture pressure drop due to missing the small features of the fracture surfaces and smoothing out their roughness.

Compliant Plate Seals: Design and Performance Simulations

2012 ◽  
Author(s):  
Hrishikesh V. Deo ◽  
Ajay Rao ◽  
Hemant Gedam
Keyword(s):  
Gas Turbines ◽  
Tip Clearance ◽  
Outer Diameter ◽  
Aircraft Engines ◽  
Steam Turbines ◽  
Flow Rates ◽  
Cfd Models ◽  
Low Leakage ◽  
And Performance ◽  
Large Rotor

Compliant Plate Seals are being developed for various turbomachinery sealing applications including gas turbines, steam turbines, aircraft engines and oil & gas compressors. These seals consist of compliant plates attached to a stator in a circumferential fashion around a rotor. The compliant plates have a slot that extends radially inwards from the seal outer diameter, and an intermediate plate extends inwards into this slot from stator. This design is capable of providing passive hydrostatic feedback forces acting on the compliant plates that balance at a small tip–clearance. Due to this self–correcting behavior, this seal is capable of providing high differential pressure capability and low leakage within a limited axial span, and non–contact operation even in the presence of large rotor transients. CFD models have been developed to predict the leakage flow rates and hydrostatic lift and blowdown forces, and a design philosophy is proposed to predict the feedback phenomenon from the CFD results.

Calculation and Simulation Azimuth Hydrostatic Thrust Bearing of a Large Alt-Azimuth Telescope

2013 ◽  
Vol 364 ◽  
pp. 28-32
Author(s):  
Long Huang ◽  
Wen Li Ma ◽  
Jin Long Huang
Keyword(s):  
Thrust Bearing ◽  
Structure Parameter ◽  
Tracking Accuracy ◽  
Low Friction ◽  
Element Analysis ◽  
Hydrostatic Bearing ◽  
Wide Range ◽  
And Performance ◽  
Large Telescopes ◽  
Main Factor

The use of hydrostatic bearing for support of telescope offers a number of potential performance advantages, but the structure parameter of bearing is the main factor which influence the bearing. The temperature rise of bearing is also important for the stiffnees of the telescope mount.In addition to the known benefit of mount stiffness and tracking accuracy from exceedingly low friction, the hydrostatic bearing provides a wide range of geometric possibilities for large telescopes [1].This paper analyzes various familiar hydrostatic bearing for the azimuth and elevation axes of telescope.Theoretical calculation and simulation show that the performance of bearing meets telescope’s design requirements.The principle and process of this work and Finite Element Analysis (FEA) are introduced in detail. According to the CFX result, the structure parameter and performance of bearing ,temperature field and pressure distribution have obtained.

scholarly journals Fabrication and Performance Evaluation of Thin Film RTD Temperature Sensor Array on a Curved Glass Surface

2011 ◽  
Vol 9 (2) ◽  
pp. 34-39 ◽  
Author(s):  
Chul-Hee Ahn ◽  
Hyoung-Hoon Kim ◽  
Sang-Hu Park ◽  
Chang-Min Son ◽  
Jeung-Sang Go
Keyword(s):  
Thin Film ◽  
Performance Evaluation ◽  
Temperature Sensor ◽  
Glass Surface ◽  
Sensor Array ◽  
Curved Glass ◽  
And Performance
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