Fluid pressure distribution in an aerated hopper

AIChE Journal ◽  
1980 ◽  
Vol 26 (2) ◽  
pp. 297-299
Author(s):  
H. Kubilay Altiner
2015 ◽  
Vol 137 (9) ◽  
Author(s):  
Joe Tien ◽  
Le Li ◽  
Ozgur Ozsun ◽  
Kamil L. Ekinci

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.


1999 ◽  
Vol 106 (4) ◽  
pp. 2204-2204 ◽  
Author(s):  
Anand A Parthasarathi ◽  
Karl Grosh ◽  
Tianying Ren ◽  
Alfred L Nuttall

Author(s):  
Moosa S. M. Al-Kharusi ◽  
Sayyad Zahid Qamar ◽  
Tasneem Pervez ◽  
Maaz Akhtar

Main motivation for this work is the need for performance evaluation of swelling (and inert) elastomer seals used in petroleum applications. Closed-form (analytical) solutions are derived for sealing pressure distribution along the elastomer seal as a function of material properties of the elastomer, seal geometry and dimensions, seal compression, and differential fluid pressure acting on the seal ends. Seal performance is also modeled and simulated numerically. Good agreement between analytical and numerical results gives confidence that the analytical solution can be used for reliable prediction of sealing behavior of the elastomer. Detailed investigation is then carried out to find out the effect of variation in seal design parameters on seal performance. For both analytical and numerical models, properties of the seal material at various stages of swelling are needed. Therefore, a series of experiments were also designed and conducted to study the effect of swelling on mechanical properties (E, G, K, and ν) of the sealing material. One major finding is that sealing pressure distribution along the seal is not constant but varies nonlinearly depending on seal parameters and loading conditions, with maximum sealing pressure occurring at the center of the seal length. Longer seals are not necessarily better; after a certain seal length, sealing pressure reaches a steady value for a given set of field conditions. As expected, higher seal compression gives higher sealing pressure. Seal compression can be increased either by tubular expansion or by selecting an elastomer that swells more, or a combination of the two. Experimental evaluation of swelling-elastomer seal performance can be very costly, and is not even possible in many cases. Numerical simulations, if validated, can be more convenient, but computational effort and cost can be high as simulations have to be run for each set of conditions. Analytical approach presented here not only gives an elegant closed-form solution, but can give reasonably accurate and much faster prediction of elastomer performance under various actual oil and gas field conditions.


2014 ◽  
Vol 628 ◽  
pp. 376-382
Author(s):  
Qiu Hua Shi ◽  
Bin Xia ◽  
Zhi Feng Wan ◽  
Ya Juan Yuan

Study on abnormal pressure of sedimentary basin is of great significance. According to the ultrasonic time difference method and measured practical data, some sectional and planar pressure distribution of Zhanhua Sag are obtained while most belong to overpressure, and the pressure distribution and the formation mechanism of high pressure are also analyzed. It is showed that the pore fluid pressure of Es3 and the upper part of Es4 members are higher in Bonan subsag and Gubei subsag and the distribution of abnormal high pressure reached a maximum at the early Es3. The disequilibrium compaction, hydrocarbon generation and some clay mineral dehydration are suggested to contribute to the formation of normal high pressure, including the rapid deposition as one of the most key factor. The lower part of Es3 and Es4 themselves within the deep high pressure system, as good lithologic reservoirs, can transport oil to the upper formation by episodic release to form allochthonous atmospheric hydrocarbon reservoirs.


2010 ◽  
Vol 44-47 ◽  
pp. 970-974
Author(s):  
Chang He Li ◽  
Jing Yao Li ◽  
Ya Li Hou

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.


Author(s):  
Ce Chen ◽  
JinFu Yang ◽  
ChaoQun Nie ◽  
Ying Cui ◽  
DaRen Yu ◽  
...  

This paper presents a theoretical analysis of the mechanism of oil whirl, oil whip, and hysteresis in oil whip. A qualitative analysis of the interrelation between whirl frequency, natural frequency, and eccentricity ratio versus speed was conducted using the rotor-bearing load balance equation. By analyzing the interrelation among whirl speed, eccentricity ratio versus speed, rotating speed, oil supply pressure and bearing load, and observing the oil-film load circumferential fluid pressure distribution in the three phases of oil-film load attenuation, instability transition, and oil-film load instability, it was found that in the whirl instability transition phase, the amplitude of rotor whirl speed exceeds half the value of rotor rotation speed, which causes the pressure change in the oil convergent wedge to change from positive to negative, and the pressure change in the divergent wedge to change from negative to positive, and the change in oil-film pressure distribution causes the instability of oil whirl; These changes in oil film pressure distribution are the indicator of oil whirl instability. An experimental study on the whirl instability in a pump supported on fluid film bearings is also presented in this paper to validate the theoretical approach.


1998 ◽  
Vol 120 (4) ◽  
pp. 820-822
Author(s):  
V. P. Astakhov ◽  
S. Abi Karam ◽  
M. O. M. Osman

This paper investigates experimentally the correlation between the cutting fluid pressure distribution in the bottom clearance (the space enclosed by the bottom of the hole being drilled from one side and the flanks of the drill head from the other) and the flank wear of BTA drills. Two types of BTA drills were studied representing two basic drill designs in the current use: single- and multi-edge drilling heads. Experiments included the study of the bottom clearance topology, the measurements of the cutting fluid pressure distribution in the bottom clearance, and the study of the tool wear topology. The results reveal the notable correlation between the cutting fluid pressure distribution in the bottom clearance and the topography of tool wear.


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