scholarly journals Measurement of Steady State Pressure Distribution and Dynamic Pressure Fluctuations During Sputtering Process

2017 ◽  
Vol 60 (6) ◽  
pp. 220-227
Author(s):  
Shuichi TAJIRI ◽  
Takanori ONISHI ◽  
Yukiko OKANO ◽  
Soichi OGAWA ◽  
Hiroshi MIMA
Keyword(s):  
Steady State ◽  
Pressure Distribution ◽  
Dynamic Pressure ◽  
Pressure Fluctuations ◽  
State Pressure

Rotordynamics of a Two-Phase Flow Twin Screw Pump

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Ameen R. A. Muhammed ◽  
Dara W. Childs
Keyword(s):  
Steady State ◽  
Pressure Distribution ◽  
Two Phase Flow ◽  
Dynamic Pressure ◽  
Phase Flow ◽  
Two Phase ◽  
Screw Pump ◽  
Lateral Forces ◽  
Starting Point ◽  
Twin Screw

Twin screw pumps are positive displacement machines. Two meshing screws connected by timing gears push the fluid trapped in the screw cavities axially from suction to discharge. Available steady state hydraulic models predict pump performance and axial pressure distribution in the chambers in single- and two-phase flow conditions. However, no model is available for their rotordynamics behavior. Due to the helix angle of the screw, the pressure distribution around the rotor is not balanced, giving rise to both static and dynamic lateral forces. The work presented here introduces a starting point for rotordynamic analysis of twin screw pumps. First, we show that the screw rotor's geometry can be represented by axisymmetric beam elements. Second, we extend the steady state hydraulic model to predict both the static and dynamic lateral forces resulting from the unbalanced pressure field. Finally, hydraulic forces are applied to the rotor to predict static, synchronous, and nonsynchronous responses. Predictions of the dynamic pressure were compared to measurements from the literature and were found to be in good agreement.

Rotordynamics of a 2-Phase Flow Twin Screw Pump

2012 ◽  
Author(s):  
Ameen R. A. Muhammed ◽  
Dara W. Childs
Keyword(s):  
Steady State ◽  
Pressure Distribution ◽  
Dynamic Pressure ◽  
Phase Flow ◽  
Two Phase ◽  
Screw Pump ◽  
Lateral Forces ◽  
Starting Point ◽  
Twin Screw ◽  
Screw Rotors

Twin-screw pumps are positive displacement machines. Two meshing screws connected by timing gears push the fluid trapped in the screw cavities axially from suction to discharge. Available steady state hydraulic models predict pump performance and axial pressure distribution in the chambers in single and two phase flow conditions. However, no model is available for their rotordynamics. Due to the helix angle of the screw, the pressure distribution around the rotor is not balanced; giving rise to both static and dynamic lateral forces. The work presented here introduces a starting point for rotordynamic analysis of twin screw-pumps. We first show that the screw rotors geometry can be represented by axisymmetric beam elements. Second, we extend the steady state hydraulic model to predict both the static and dynamic lateral forces resulting from the unbalanced pressure field. Finally, hydraulic forces are applied to the rotor to predict static, synchronous and nonsynchronous responses. Predictions of the dynamic pressure were compared to measurements from the literature and were found to be in good agreement.

Asymptotic Analysis of a Finite Gas Slider Bearing of Narrow Geometry

1983 ◽  
Vol 105 (3) ◽  
pp. 491-495 ◽  
Author(s):  
J. J. Shepherd ◽  
R. C. DiPrima
Keyword(s):  
Steady State ◽  
Asymptotic Analysis ◽  
Pressure Distribution ◽  
Asymptotic Expansions ◽  
Matched Asymptotic Expansions ◽  
Slider Bearing ◽  
Load Bearing ◽  
Bearing Number ◽  
Isothermal Gas ◽  
State Pressure

The method of matched asymptotic expansions is used to analyze the steady state pressure distribution and load bearing properties of a finite rectangular isothermal gas slider bearing when ε, the ratio of transverse to longitudinal dimensions of the bearing, is small and the bearing number Λ is moderate. General expressions for the pressure and load are obtained. Specific results are given for bearings with shallow crowning. The effects of the bearing number becoming large and the interaction between the two effects ε→0 and Λ→∞ are discussed.

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