A Heat Transfer Model of Grinding Process Based on Energy Partition Analysis and Grinding Fluid Cooling Application

2017 ◽  
Vol 139 (12) ◽  
Author(s):  
Guoxu Yin ◽  
Ioan D. Marinescu
Keyword(s):  
Heat Transfer ◽  
Contact Area ◽  
Frictional Resistance ◽  
Heat Transfer Model ◽  
Heat Energy ◽  
Grinding Wheel ◽  
Transfer Model ◽  
Grinding Process ◽  
Energy Partition ◽  
Grinding Fluid

In the grinding process, high temperature in grinding area is generated by the frictional resistance between workpiece and abrasive grains on the grinding wheel cylindrical surface. Grinding fluid application is an optimal option to reduce the thermal effect and crack on the workpiece ground surface. In this paper, a grinding process heat transfer model with various grinding fluid application is introduced based on computational fluid dynamics (CFD) methodology. The effect of specific heat, viscosity, and surface tension of grinding fluid are taken into account. In the model, the grinding contact area is considered as a heating resource. Most of the heat energy is conducted into the workpiece. The rest of the energy is taken away by the grinding wheel, grinding fluid, and chips. How many percentage of the generated heat is conducted into the workpiece is a key issue, namely, the energy partition ratio ε. An energy partition equation is introduced in this paper with the cooling effect of different grinding fluid. Generated heat energy based on the calculation from energy partition equation is applied on the grinding contact area in the heat transfer model.

A Model of the Fluid Convective Cooling in Grinding Process

2013 ◽  
Vol 797 ◽  
pp. 299-304 ◽  
Author(s):  
Lei Zhang ◽  
Michael N. Morgan
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Convective Heat Transfer Coefficient ◽  
Grinding Wheel ◽  
Process Conditions ◽  
Transfer Model ◽  
Grinding Process ◽  
Fluid Properties ◽  
Grinding Conditions

The grinding process has particular interest in that contact temperatures have great significance for quality and integrity of machined surfaces. Hardened surfaces may be damaged by softening and or being stressed, being hardened or re-hardened, burned or cracked. It is important in grinding for the fluid to remove heat from the grinding contact zone to avoid thermal damage to the workpiece surface and/or sub-surface layers. The cooling effect of grinding fluid can be quantified by the convective heat transfer coefficient (CHTC) acting in the grinding zone. This paper presents values of the CHTC based on measured grinding temperatures. The paper also presents a new convective heat transfer model based on principles of applied fluid dynamics and heat transfer. Predicted values for the CHTC calculated from the model are compared with results from experiment obtained under a range of grinding conditions and with experimental data. The results demonstrate that the new CHTC model improves the accuracy of prediction and helps explain the variation in the value of CHTC under varying process conditions. Results also show that convection efficiency strongly depends on the grinding wheel speed, grinding arc length and fluid properties.

Study on Properties of Grinding Fluid Jet and Nozzle Position for Super-High Speed Point Grinding

2010 ◽  
Vol 135 ◽  
pp. 452-457
Author(s):  
Shi Chao Xiu ◽  
Ji Man Luo ◽  
Zhi Li Sun
Keyword(s):  
Contact Area ◽  
High Speed ◽  
Fluid Velocity ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Pressure Balance ◽  
Balance Principle ◽  
Grinding Fluid ◽  
High Speed Grinding ◽  
Grinding Machine

Super-high speed point grinding is a new high-speed grinding technology with some excellent machining performances. In such a grinding process, there is a high-speed airflow rotating around the edge of grinding wheel which hinders the grinding fluid from injecting into the contact area and makes the fluid atomization and splash during grinding process, so as to decrease the ratio of effective grinding fluid into contact area and affect the surface integrity of workpiece. In this paper, the structure and properties of grinding fluid jet is analyzed, the velocity distribution field of the round turbulent jet is discussed theoretically and simulated. Based on the pressure balance principle, a mathematical model is established for the jet velocity at the fluid nozzle, which enables the grinding fluid to pass through the high speed airflow and enter into the contact area. According to the analysis of the grinding fluid velocity in the jet core, an engineering formula is given to calculate the position limit of nozzle during grinding process, as well as a practical design example for the high speed grinding machine is presented.

Theoretical Post-Dryout Heat Transfer Model

2018 ◽  
Vol 1 (1) ◽  
pp. 142-150
Author(s):  
Murat Tunc ◽  
Ayse Nur Esen ◽  
Doruk Sen ◽  
Ahmet Karakas
Keyword(s):  
Heat Transfer ◽  
Droplet Diameter ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Operating Pressure ◽  
Vertical Pipe ◽  
Two Phase ◽  
Experimental Values ◽  
Reactor Operating ◽  
Coolant System

A theoretical post-dryout heat transfer model is developed for two-phase dispersed flow, one-dimensional vertical pipe in a post-CHF regime. Because of the presence of average droplet diameter lower bound in a two-phase sparse flow. Droplet diameter is also calculated. Obtained results are compared with experimental values. Experimental data is used two-phase flow steam-water in VVER-1200, reactor coolant system, reactor operating pressure is 16.2 MPa. On heater rod surface, dryout was detected as a result of jumping increase of the heater rod surface temperature. Results obtained display lower droplet dimensions than the experimentally obtained values.

An Engine Heat Transfer Model for Comprehensive Thermal Simulations

2006 ◽  
Author(s):  
Filip Kitanoski ◽  
Wolfgang Puntigam ◽  
Martin Kozek ◽  
Josef Hager
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Thermal Simulations

Developing a CFD heat transfer model for applying high expansion foam in an LNG spill

2021 ◽  
Vol 71 ◽  
pp. 104456
Author(s):  
Zhuoran Zhang ◽  
Pratik Krishnan ◽  
Zeren Jiao ◽  
M. Sam Mannan ◽  
Qingsheng Wang
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Expansion Foam

Study on Edge Contact Area and Surface Integrity of Workpiece in Point Grinding Process

2009 ◽  
Vol 407-408 ◽  
pp. 577-581
Author(s):  
Shi Chao Xiu ◽  
Zhi Jie Geng ◽  
Guang Qi Cai
Keyword(s):  
Surface Integrity ◽  
Contact Area ◽  
High Speed ◽  
Ground Surface ◽  
Depth Of Cut ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Edge Contact ◽  
Cylindrical Grinding ◽  
Theoretic Foundations

During cylindrical grinding process, the geometric configuration and size of the edge contact area between the grinding wheel and workpiece have the heavy effects on the workpiece surface integrity. In consideration of the differences between the point grinding and the conventional high speed cylindrical grinding, the geometric and mathematic models of the edge contact area in point grinding were established. Based on the models, the numerical simulation for the edge contact area was performed. By means of the point grinding experiment, the effect mechanism of the edge contact area on the ground surface integrity was investigated. These will offer the applied theoretic foundations for optimizing the point grinding angles, depth of cut, wheel and workpiece speed, geometrical configuration and size of CBN wheel and some other grinding parameters in point grinding process.

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