An Investigation Hydrodynamic Fluid Pressure at Wedge-Shaped Gap between Grinding Wheel and Workpiece

2010 ◽  
Vol 44-47 ◽  
pp. 970-974
Author(s):  
Chang He Li ◽  
Jing Yao Li ◽  
Ya Li Hou
Keyword(s):  
Pressure Distribution ◽  
Fluid Pressure ◽  
Hydrodynamic Pressure ◽  
Contact Length ◽  
Coolant Fluid ◽  
Grinding Wheel ◽  
Maximum Pressure ◽  
Work Surface ◽  
Good Surface ◽  
Peripheral Surface

In the grinding process, conventional method of flood delivering coolant fluid by a nozzle in order to achieve good surface integrity. However, hydrodynamic fluid pressure can be generated ahead of the contact zone due to the wedge effect between wheel peripheral surface and work surface. In the paper, a theoretical hydrodynamic pressure modeling is presented for flow of coolant fluid through the grinding zone in flood delivery grinding. Moreover, coolant induced force can be calculated by integrate the hydrodynamic pressure distribution over the whole contact length. The theoretical results show that the hydrodynamic pressure was proportion to grinding wheel velocity, and inverse proportion to the minimum gap between wheel and work surface and the maximum pressure value was generated just in the minimum gap region in which higher fluid pressure gradient occuring. It can also be concluded the pressure distribution was uniform in the direction of width of wheel except at the edge of wheel because of the side-leakage.

Mathematical Model of Hydrodynamic Fluid Pressure on Smooth and Real Surface

2010 ◽  
Vol 135 ◽  
pp. 429-434
Author(s):  
Chang He Li ◽  
Li Li Wang ◽  
Guo Yu Liu
Keyword(s):  
Fluid Pressure ◽  
Elastohydrodynamic Lubrication ◽  
Hydrodynamic Pressure ◽  
Coolant Fluid ◽  
Grinding Wheel ◽  
Maximum Pressure ◽  
Real Surface ◽  
Work Surface ◽  
Peripheral Surface ◽  
Wedge Effect

Conventional method of flood delivering coolant fluid by a nozzle in order to achieve high process performance. However, hydrodynamic fluid pressure can be generated ahead of the contact zone due to the wedge effect between wheel peripheral surface and work surface. In the paper, theoretical hydrodynamic pressure modeling were presented for flow of coolant fluid through the grinding zone in flood delivery grinding using smooth and roughness surface grinding wheel respectively. The simulation results show that the hydrodynamic pressure was proportion to grinding wheel velocity, and inverse proportion to the minimum gap between wheel and work surface and the maximum pressure value was generated just in the minimum gap region in which higher fluid pressure gradient occuring. It can also be concluded the surface roughness of grinding wheel and workpiece makes the contact zone’s hydrodynamic pressure rough and unstable, i.e. the value curve considering roughness is not smooth, leading to the micro-elastohydrodynamic lubrication phenomenon.

Theoretical Analysis and Experimental Investigation into Hydrodynamic Pressure and Coolant Lift Force in Flood Delivery Grinding

2010 ◽  
Vol 97-101 ◽  
pp. 1836-1840
Author(s):  
Ya Li Hou ◽  
Fu Xin Yao ◽  
Chang He Li ◽  
Yu Cheng Ding
Keyword(s):  
Pressure Distribution ◽  
Contact Zone ◽  
High Performance ◽  
Fluid Pressure ◽  
Hydrodynamic Pressure ◽  
Experimental Results ◽  
Coolant Fluid ◽  
Grinding Wheel ◽  
Maximum Pressure ◽  
Work Surface

In the grinding process, conventional method of flood delivering coolant fluid by a nozzle in order to achieve high performance finishing. However, hydrodynamic fluid pressure can be generated ahead of the contact zone due to the wedge effect between wheel peripheral surface and work surface. In the paper, a theoretical hydrodynamic pressure modeling is presented for flow of coolant fluid through the grinding zone in flood delivery grinding. Moreover, coolant induced force can be calculated by integrate the hydrodynamic pressure distribution over the whole contact length. The theoretical results show that the hydrodynamic pressure was proportion to grinding wheel velocity, and inverse proportion to the minimum gap between wheel and work surface and the maximum pressure value was generated just in the minimum gap region in which higher fluid pressure gradient occuring. It can also be concluded the pressure distribution was uniform in the direction of width of wheel except at the edge of wheel because of the side-leakage. Furthermore, the hydrodynamic pressure and coolant induced force at wedge-like zone were also investigated experimentally. The experimental results show the theoretical model is agreement with experimental results and the model can well forecast hydrodynamic pressure distribution at contact zone between grinding wheel and workpiece.

Model and Simulation of Fluid Hydrodynamic Pressure at the Cutting Zone Considering the Surface Roughness

2010 ◽  
Vol 118-120 ◽  
pp. 655-659
Author(s):  
Chang He Li ◽  
Yan Zhou ◽  
Guang Qi Cai
Keyword(s):  
Surface Roughness ◽  
Fluid Pressure ◽  
Elastohydrodynamic Lubrication ◽  
Hydrodynamic Pressure ◽  
Coolant Fluid ◽  
Grinding Wheel ◽  
Maximum Pressure ◽  
Work Surface ◽  
Model And Simulation ◽  
Cutting Zone

The theoretical hydrodynamic pressure modeling were presented for flow of coolant fluid through the grinding zone in flood delivery grinding using roughness surface grinding wheel. The simulation results show that the hydrodynamic pressure was proportion to grinding wheel velocity, and inverse proportion to the minimum gap between wheel and work surface and the maximum pressure value was generated just in the minimum gap region in which higher fluid pressure gradient occuring. It can also be concluded the surface roughness of grinding wheel and workpiece makes the contact zone’s hydrodynamic pressure rough and unstable, i.e. the value curve considering roughness is not smooth, leading to the micro-elastohydrodynamic lubrication phenomenon.

Numerical Simulation of Hydrodynamic Fluid Pressure in Grinding Zone with Resin-Bonded Diamond Grinding Wheel

2010 ◽  
Vol 426-427 ◽  
pp. 668-673
Author(s):  
Ya Li Hou ◽  
Chang He Li
Keyword(s):  
Numerical Simulation ◽  
Fluid Pressure ◽  
Hydrodynamic Pressure ◽  
Coolant Fluid ◽  
Grinding Wheel ◽  
Maximum Pressure ◽  
Delivery Mode ◽  
Diamond Grinding Wheel ◽  
Diamond Grinding ◽  
Grinding Fluid

In the grinding process, grinding fluid is delivered for the purposes of chip flushing, cooling, lubrication and chemical protection of work surface. Lubrication and cooling are the most important roles provided by a grinding fluid. Hence, the conventional method of flood delivering coolant fluid by a nozzle in order to achieve high process performance purposivelly. However, hydrodynamic fluid pressure can be generated ahead of the grinding zone due to the wedge effect between wheel peripheral surface and part surface. In the paper, a theoretical hydrodynamic pressure modeling is presented for flow of coolant fluid through the grinding zone in flood delivery mode in the surface grinding using resin-bonded diamond grinding wheel, which based on Navier-Stokes equation and continuous formulae. The numerical simulation results showed that the hydrodynamic pressure was proportion to grinding wheel velocity, and inverse proportion to the minimum gap between wheel and workpiece and the maximum pressure was generated just in the minimum clearance region in which higher fluid pressure gradient occur. It can also be concluded the pressure distribution was uniform in the direction of width of wheel except at the edge of wheel because of the side-leakage.

Model and Simulation of Slurry Velocity and Hydrodynamic Pressure in Abrasive Jet Finishing with Grinding Wheel as Restraint

2008 ◽  
Vol 375-376 ◽  
pp. 449-453 ◽  
Author(s):  
Chang He Li ◽  
Ya Li Hou ◽  
Shi Chao Xiu ◽  
Guang Qi Cai
Keyword(s):  
Laminar Flow ◽  
Fluid Pressure ◽  
Three Dimensional ◽  
Hydrodynamic Pressure ◽  
Surface Velocity ◽  
Navier Stokes ◽  
Grinding Wheel ◽  
Maximum Pressure ◽  
Navier Stokes Equation ◽  
Model And Simulation

The models for three-dimensional velocity and hydrodynamic pressure of abrasive fluid in contact zone between wheel and workpiece on abrasive jet finishing with wheel as restraint were presented based on Navier-Stokes equation and continuous formulae. The emulational results shown that the hydrodynamic pressure was proportion to grinding wheel velocity, and inverse proportion to the minimum gap between wheel and workpiece and the maximum pressure was generated just in the minimum clearance region in which higher fluid pressure gradient occur. It can also be concluded the pressure distribution was uniform in the direction of width of wheel except at the edge of wheel because of the side-leakage. The velocity in the x direction was dominant and the side-leakage in the y direction existed. The velocity in the z direction was smaller than the others because of the assumption of laminar flow. The smaller the gap distance is, the larger the velocity in the x direction. The magnitude of the velocity is also proportional to the surface velocity of the wheel.

Theoretical Analysis and Experimental Verification of Validity Finished by Abrasive Jet with Grinding Wheel as Restraint

2008 ◽  
Vol 53-54 ◽  
pp. 39-44
Author(s):  
Chang He Li ◽  
Shi Chao Xiu ◽  
Yu Cheng Ding ◽  
Guang Qi Cai
Keyword(s):  
Ground Surface ◽  
Hydrodynamic Pressure ◽  
Machining Process ◽  
Grinding Wheel ◽  
Workpiece Material ◽  
Machined Surface ◽  
Mean Values ◽  
Work Surface ◽  
Geometry Parameter ◽  
Parameter Values

The integration manufacturing technology is a kind of compound precision finishing process that combined grinding with abrasive jet finishing, in which inject slurry of abrasive and liquid solvent into grinding zone between grinding wheel and work surface under no radial feed condition when workpiece grinding were accomplished. The abrasive particles are driven and energized by the rotating grinding wheel and liquid hydrodynamic pressure and increased slurry speed between grinding wheel and work surface to achieve micro removal finishing. In the paper, the machining process validity was verified by experimental investigation. Experiments were performed with plane grinder M7120 and workpiece material 40Cr steel which was ground with the surface roughness mean values of Ra=0.6μm. The machined surface morphology was studied using Scanning Electron Microscope (SEM) and metallography microscope and microcosmic geometry parameters were measured with TALYSURF5 instrument respectively. The experimental results show the novelty process method, not only can obviously diminish longitudinal geometry parameter values of ground surface, but also can attain isotropy surface and uniformity veins at parallel and perpendicular machining direction. Furthermore, the finished surface has little comparability compared to grinding machining surface and the process validity was verified.

End Effect Attenuation in Tapered Roller Contacts

2009 ◽  
Author(s):  
Emanuel Diaconescu
Keyword(s):  
Pressure Distribution ◽  
Finite Length ◽  
Contact Length ◽  
Maximum Pressure ◽  
End Effect ◽  
End Effects ◽  
Maximum Value ◽  
Line Contacts ◽  
Tapered Roller

The end effect attenuation in finite length line contacts is mainly approached for cylindrical bodies. Multi-radius crowning may remove end effects in tapered roller contacts. Another method for leveling maximum pressure in these contacts is the use of polynomial generatrix. This paper investigates the effect of this generatrix in tapered roller contacts. An improved pressure distribution is obtained. This has a nearly flat maximum value along most of contact length.

Performance Evaluation of Minimum Quantity Cooling Lubrication Using CBN Grinding Wheel

2010 ◽  
Vol 97-101 ◽  
pp. 1827-1831 ◽  
Author(s):  
Chang He Li ◽  
Chao Du ◽  
Guo Yu Liu ◽  
Yan Zhou
Keyword(s):  
Supply System ◽  
Cutting Fluid ◽  
Coolant Fluid ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Minute Amount ◽  
Work Surface ◽  
Promising Solution ◽  
G Ratio ◽  
Cbn Grinding Wheel

In the grinding process, conventional method of flood delivering coolant fluid by a nozzle in order to achieve chip flushing, cooling, lubrication and chemical protection of work surface. However the conventional flood supply system demands more resources for operation, maintenance, and disposal, and results in higher environmental and health problems. Therefore, there are critical needs to reduce the use of cutting fluid in grinding process, and MQCL grinding is a promising solution. MQCL grinding refers to the use of cutting fluids of only a minute amount typically of a flow rate of 10 to 100 ml/hour which is about hundreds orders of magnitude less than the amount commonly used in flood cooling condition. The evaluation of the performance of the MQCL technique in grinding consisted of analyzing the behavior of the tangential cutting force, G-ratio, Surface morphology and roughness. The results presented here are expected to lead to technological and ecological gains in the grinding process using MQCL.

Investigation into Fluid Velocity Field of Wedge-Shaped Gap in Grinding

2010 ◽  
Vol 37-38 ◽  
pp. 593-598 ◽  
Author(s):  
Chang He Li ◽  
Zhen Lu Han ◽  
Jing Yao Li
Keyword(s):  
Velocity Field ◽  
Fluid Velocity ◽  
Fluid Pressure ◽  
Surface Velocity ◽  
Navier Stokes ◽  
Coolant Fluid ◽  
Navier Stokes Equation ◽  
Part Surface ◽  
Peripheral Surface ◽  
Fluid Velocity Field

In the grinding process, grinding fluid is delivered for the purposes of chip flushing, cooling, lubrication and chemical protection of work surface. Hence, the conventional method of flood delivering coolant fluid by a nozzle in order to achieve high process performance purposivelly. However, hydrodynamic fluid pressure can be generated ahead of the grinding zone due to the wedge effect between wheel peripheral surface and part surface. In this paper, a theoretical fluid velocity field modeling is presented for flow of coolant fluid of wedge-shaped gap in flood delivery surface grinding, which is based on navier-stokes equation and continuous formulae. The numerical simulation results showed that the velocity in the x direction was dominant and the side-leakage in the y direction existed. The velocity in the z direction was smaller than the others because of the assumption of laminar flow. The smaller the gap is, the larger the velocity in the x direction. The magnitude of the velocity is also proportional to the surface velocity of the wheel.

Dynamics of Interstitial Fluid Pressure in Extracellular Matrix Hydrogels in Microfluidic Devices

2015 ◽  
Vol 137 (9) ◽  
Author(s):  
Joe Tien ◽  
Le Li ◽  
Ozgur Ozsun ◽  
Kamil L. Ekinci
Keyword(s):  
Extracellular Matrix ◽  
Pressure Distribution ◽  
Interstitial Fluid ◽  
Scaling Laws ◽  
Fluid Pressure ◽  
Interstitial Fluid Pressure ◽  
External Loading ◽  
Interstitial Pressure ◽  
Time Resolved ◽  
Long Time

In order to understand how interstitial fluid pressure and flow affect cell behavior, many studies use microfluidic approaches to apply externally controlled pressures to the boundary of a cell-containing gel. It is generally assumed that the resulting interstitial pressure distribution quickly reaches a steady-state, but this assumption has not been rigorously tested. Here, we demonstrate experimentally and computationally that the interstitial fluid pressure within an extracellular matrix gel in a microfluidic device can, in some cases, react with a long time delay to external loading. Remarkably, the source of this delay is the slight (∼100 nm in the cases examined here) distension of the walls of the device under pressure. Finite-element models show that the dynamics of interstitial pressure can be described as an instantaneous jump, followed by axial and transverse diffusion, until the steady pressure distribution is reached. The dynamics follow scaling laws that enable estimation of a gel's poroelastic constants from time-resolved measurements of interstitial fluid pressure.

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