A Study of CFD Models for Investigating the Water Beam Assisted Form Error In-Process Optical Measurement

2010 ◽  
Vol 437 ◽  
pp. 472-476 ◽  
Author(s):  
Y.H. Lai ◽  
Y. Gao ◽  
Y. Zhang ◽  
J.X. Wang
Keyword(s):  
Measurement Method ◽  
Optical Measurement ◽  
Geometric Model ◽  
Computational Approach ◽  
Error Measurement ◽  
Form Error ◽  
Machining Processes ◽  
Cfd Models ◽  
Mesh Adaption ◽  
Computational Fluid Dynamics Cfd

The opaque coolant used in the removal machining processes has an inaccessibility problem for the form error in-process optical measurement. The water beam assisted approach should be one of the possible solutions for the problem. In this project, we propose to study the measurement process using the computational approach for better understanding of the process and for validating the models and settings. The experimental results and the Computational Fluid Dynamics (CFD) results are found close to each other. This gives us confidence in using the proposed CFD models and settings. The proposed new transparent window definition is suitable. The models and settings established include geometric model, mesh adaption model, domain settings, coolant concentration representation, expressions, boundary conditions, and CFX solver settings. The developed CFD models and settings will be useful in our further studies of the form error measurement method.

Modeling of Compressor Drum Cavities With Radial Inflow

2016 ◽  
Author(s):  
D. Amirante ◽  
Z. Sun ◽  
J. W. Chew ◽  
N. J. Hills ◽  
N. R. Atkins
Keyword(s):  
Thermal Stratification ◽  
Turbulence Modeling ◽  
Navier Stokes ◽  
Inflow Rate ◽  
Cfd Models ◽  
Flow And Heat Transfer ◽  
Rotating Discs ◽  
Computational Fluid Dynamics Cfd ◽  
Inlet Conditions ◽  
Cooling Air

Reynolds-Averaged Navier-Stokes (RANS) computations have been conducted to investigate the flow and heat transfer between two co-rotating discs with an axial throughflow of cooling air and a radial bleed introduced from the shroud. The computational fluid dynamics (CFD) models have been coupled with a thermal model of the test rig, and the predicted metal temperature compared with the thermocouple data. CFD solutions are shown to vary from a buoyancy driven regime to a forced convection regime, depending on the radial inflow rate prescribed at the shroud. At a high radial inflow rate, the computations show an excellent agreement with the measured temperatures through a transient rig condition. At a low radial inflow rate, the cavity flow is destabilized by the thermal stratification. Good qualitative agreement with the measurements is shown, although a significant over-prediction of disc temperatures is observed. This is associated with under prediction of the penetration of the axial throughflow into the cavity. The mismatch could be the result of strong sensitivity to the prescribed inlet conditions, in addition to possible shortcomings in the turbulence modeling.

scholarly journals Computational Approach to Seasonal Changes of Living Leaves

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Ying Tang ◽  
Dong-Yan Wu ◽  
Jing Fan
Keyword(s):  
Seasonal Changes ◽  
Markov Chain Model ◽  
Geometric Model ◽  
Environmental Parameters ◽  
Computational Approach ◽  
Chain Model ◽  
Color Changes ◽  
Mass Spring Model ◽  
Scanned Image ◽  
Mass Spring

This paper proposes a computational approach to seasonal changes of living leaves by combining the geometric deformations and textural color changes. The geometric model of a leaf is generated by triangulating the scanned image of a leaf using an optimized mesh. The triangular mesh of the leaf is deformed by the improved mass-spring model, while the deformation is controlled by setting different mass values for the vertices on the leaf model. In order to adaptively control the deformation of different regions in the leaf, the mass values of vertices are set to be in proportion to the pixels' intensities of the corresponding user-specified grayscale mask map. The geometric deformations as well as the textural color changes of a leaf are used to simulate the seasonal changing process of leaves based on Markov chain model with different environmental parameters including temperature, humidness, and time. Experimental results show that the method successfully simulates the seasonal changes of leaves.

Deformation-free form error measurement of thin, plane-parallel optics floated on a heavy liquid

2010 ◽  
Vol 49 (10) ◽  
pp. 1849 ◽  
Author(s):  
Jiyoung Chu ◽  
Ulf Griesmann ◽  
Quandou Wang ◽  
Johannes A. Soons ◽  
Eric C. Benck
Keyword(s):  
Heavy Liquid ◽  
Free Form ◽  
Error Measurement ◽  
Form Error ◽  
Plane Parallel

The Effect of Bench Arrangements on the Natural Ventilation of a Multispan Greenhouse

2013 ◽  
Author(s):  
Sunita Kruger ◽  
Leon Pretorius
Keyword(s):  
Fluid Dynamics ◽  
Natural Ventilation ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Low Velocity ◽  
Lower Velocity ◽  
Cfd Models ◽  
Temperature Distributions ◽  
Computational Fluid Dynamics Cfd ◽  
Plant Level

In this paper, the influence of various bench arrangements on the microclimate inside a two-span greenhouse is numerically investigated using three-dimensional Computational Fluid Dynamics (CFD) models. Longitudinal and peninsular arrangements are investigated for both leeward and windward opened roof ventilators. The velocity and temperature distributions at plant level (1m) were of particular interest. The research in this paper is an extension of two-dimensional work conducted previously [1]. Results indicate that bench layouts inside the greenhouse have a significant effect on the microclimate at plant level. It was found that vent opening direction (leeward or windward) influences the velocity and temperature distributions at plant level noticeably. Results also indicated that in general, the leeward facing greenhouses containing either type of bench arrangement exhibit a lower velocity distribution at plant level compared to windward facing greenhouses. The latter type of greenhouses has regions with relatively high velocities at plant level which could cause some concern. The scalar plots indicate that more stagnant areas of low velocity appear for the leeward facing greenhouses. The windward facing greenhouses also display more heterogeneity at plant level as far as temperature is concerned.

A new optical measurement method for verifying the exact change of thin films on the QZ blanks with ellipsometer

2009 ◽  
Author(s):  
Songbae Moon ◽  
Seong-Yoon Kim ◽  
Gyung-Yoon Bang ◽  
Byung-Gook Kim ◽  
Sang-Gyun Woo ◽  
...  
Keyword(s):  
Thin Films ◽  
Measurement Method ◽  
Optical Measurement ◽  
Optical Measurement Method
Sign in / Sign up

Export Citation Format

Share Document