The Experts below are selected from a list of 270 Experts worldwide ranked by ideXlab platform
K N Lie - One of the best experts on this subject based on the ideXlab platform.
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rotation effects on hybrid air journal bearings
Tribology International, 2003Co-Authors: K N LieAbstract:Abstract Rotation effects of hybrid air journal bearings with multi-arrays of Orifice feedings are investigated numerically. Porous air bearings are also solved for comparison. The results show that bearing load capacity W increases faster with eccentricity ratio e than with rotation speed, i.e. bearing number Be. There are optimum Orifice diameters, i.e. optimum feeding parameters λ o , which give maximum load capacity W for Orifice feeding; but for porous feeding, load capacity W increases with feeding parameters λ p . It was found that the load capacity increases with feeding arrays of Orifices and five rows of Orifice feedings can approximate the operations of porous bearings very well. It was also found that load capacity W does not increase further when air supply pressure exceeds 5 atm because there is a critical pressure ratio through Orifice (e.g. ( P o / P s )
Kewen Peng - One of the best experts on this subject based on the ideXlab platform.
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the self propelled force model of a multi Orifice nozzle for radial jet drilling
Journal of Natural Gas Science and Engineering, 2015Co-Authors: Jingbin Li, Xianzhi Song, Zhongwei Huang, Ruiyue Yang, Gensheng Li, Kewen PengAbstract:Abstract Radial jet drilling (RJD) is an effective method for the stimulation, exploration, and development of oil and gas resources. The multi-Orifice nozzle is a type of highly efficient nozzle applied in RJD. It generates the self-propelled force to pull a connected hose moving forward to form a radial hole. However, there are few studies on the self-propelled ability of the nozzle, and there is no model for the calculation of the self-propelled force. This paper developed a convenient model to calculate the self-propelled force and defined a factor to represent the self-propelled ability of the nozzle. The proposed model was validated by means of experiment and numerical simulation. To achieve a stronger self-propelled ability, we investigated the effects of the number, angle, and diameter of the Orifices on its self-propelled ability. The results show that the forward Orifices exert a negative effect on the self-propelled ability, whereas their angles present a positive effect. With an optimal angle, the backward Orifices primarily generate the self-propelled force. Although an enlarged Orifice diameter can improve the performance of the nozzle, it still has an optimal value for the limitation of flow rate and jet pressure. This study provides a reference for the design of multi-Orifice nozzles and hydraulic parameters for radial jet drilling technology.
Takefumi Kanda - One of the best experts on this subject based on the ideXlab platform.
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flow control valve for pneumatic actuators using particle excitation by pzt vibrator
Sensors and Actuators A-physical, 2009Co-Authors: Daisuke Hirooka, Koichi Suzumori, Takefumi KandaAbstract:This paper reports a new flow control valve for pneumatic actuators that has a lightweight and simple structure and uses particle excitation by PZT vibrator. The flow control valve in this report consists of an Orifice plate which has plural Orifices, PZT vibrator which is adhered on the Orifice plate and iron particles. The valve is normally closed, because air flow carries the particles on to the Orifice and particles seal the air flow. Because the Orifice plate excitation by the PZT vibrator works to make the particles away from the Orifice plate, the air flows through the Orifices. It is driven at resonance mode and can be used as a variable speed controller for pneumatic actuators. The new flow control valve avoids the stopping shock of pneumatic actuators at the stroke ends while retaining the advantages of pneumatic actuators.
Shanfang Huang - One of the best experts on this subject based on the ideXlab platform.
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study on discharge coefficient of perforated Orifices as a new kind of flowmeter
Experimental Thermal and Fluid Science, 2013Co-Authors: Shanfang Huang, Dong WangAbstract:Abstract A perforated Orifice is promising in measuring flowrates accurately as a differential pressure device. In this study, the discharge coefficient of a perforated Orifice, characterizing the relationship between the volumetric flowrate and the pressure drop across the Orifice is presented. Different structures are tested experimentally including Orifice thickness, porosity, hole distribution and upstream disturbance. For each case, a wide range of flowrate was tested in a horizontal single-phase water pipe with an I.D. of 29 mm. For comparison, the discharge coefficient was also obtained for the corresponding standard Orifice with the same porosity and thickness. Meanwhile, the effect on the discharge coefficients of the structural parameters was assessed in terms of pressure drop. The theoretical analysis shows that a perforated Orifice yields a weaker distortion to the flow than the corresponding standard Orifice, indicating a lower pressure drop and a more stable flow field for the former. The experimental results show that the discharge coefficient of a perforated Orifice is 22.5–25.6% larger but with a weaker scattering than that of the corresponding standard Orifice. Furthermore, a perforated Orifice has a lower critical Reynolds number and a stronger anti-disturbance ability. As a flowmeter, the perforated Orifice is comparable to the newly developed differential pressure Orifices, e.g. V-cone and slotted Orifices, but with a simpler structure.
Jingbin Li - One of the best experts on this subject based on the ideXlab platform.
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the self propelled force model of a multi Orifice nozzle for radial jet drilling
Journal of Natural Gas Science and Engineering, 2015Co-Authors: Jingbin Li, Xianzhi Song, Zhongwei Huang, Ruiyue Yang, Gensheng Li, Kewen PengAbstract:Abstract Radial jet drilling (RJD) is an effective method for the stimulation, exploration, and development of oil and gas resources. The multi-Orifice nozzle is a type of highly efficient nozzle applied in RJD. It generates the self-propelled force to pull a connected hose moving forward to form a radial hole. However, there are few studies on the self-propelled ability of the nozzle, and there is no model for the calculation of the self-propelled force. This paper developed a convenient model to calculate the self-propelled force and defined a factor to represent the self-propelled ability of the nozzle. The proposed model was validated by means of experiment and numerical simulation. To achieve a stronger self-propelled ability, we investigated the effects of the number, angle, and diameter of the Orifices on its self-propelled ability. The results show that the forward Orifices exert a negative effect on the self-propelled ability, whereas their angles present a positive effect. With an optimal angle, the backward Orifices primarily generate the self-propelled force. Although an enlarged Orifice diameter can improve the performance of the nozzle, it still has an optimal value for the limitation of flow rate and jet pressure. This study provides a reference for the design of multi-Orifice nozzles and hydraulic parameters for radial jet drilling technology.
