Conductance calculation of slot channels in laminar gas flow regime at small pressure difference

Salikeev, S.; Бурмистров, А. В.; Bronshtein, M.; Fomina, M.

doi:10.1016/j.vacuum.2013.02.009

Cited by 6 publications

(6 citation statements)

References 6 publications

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“…Verification of the model is carried out by comparison of numerical calculations of gas mass flow rate and conductance with experimental data obtained by blowing-through of the slot channels 1, 2. The experimental unit and the experimental technique were presented in [3][4][5]. Some results of the numerical solution of the system (6)-(10) in comparison with experimental values are presented in Fig.…”

Section: Verification Of the Calculation Methodsmentioning

confidence: 99%

“…The comparison of the conductance values calculated according to (11), (13) and experimental data [4,5] in molecular, transient and viscous flow regimes are presented in Fig. 5 and Fig.…”

Section: Verification Of the Calculation Methodsmentioning

confidence: 99%

“…In viscous flow regime the conductance of the channels 1, 2 is calculated according to the relationships [4,5]…”

Section: Problem Formulationmentioning

confidence: 99%

“…l ef is the channel effective length; P 1 and T 1 are the pressure and the temperature at the channel inlet; τ = P 2 /P 1 is the pressure ratio (P 2 is the pressure at the channel outlet); R G is the gas constant. The relationships (2) -(5) were experimentally verified [3][4][5]. But to cover all the range of non-contact pumps operating pressures relationships for conductance calculation of the channels 1, 2 in transient flow regime are necessary.…”

Section: Problem Formulationmentioning

confidence: 99%

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Conductance Calculation Of Slot Channels with Variable Cross Section

Бурмистров¹,

Salikeev²,

Bronshtein³

et al. 2015

Vak Forsch Prax

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The range of operation pressures of non‐contact vacuum pumps may reach six decades, and flow regime in slot channels of the rotor mechanism may vary from molecular flow to viscous flow. This article is a continuation of a series of authors‘ publications dedicated to the development of a method which makes it possible to calculate promptly the conductance of slot channels with complex contoured geometry with the minimal clearance at a certain point along gas flow direction for all three gas flow regimes: molecular, transient and viscous. The numerical solution of the differential equations system (equations of motion, energy, continuity and state) is used for calculation of mass flow rate in transient gas flow regime. On the basis of the numerical calculation results the relationship is obtained which represents a smooth joining of the data for molecular and viscous flow regimes. Verification of the model and the obtained relationship is carried out by comparison of numerical calculation results of gas mass flow rate and conductance with experimental data obtained by blowing‐through of slot channels. The maximal deviation of calculation according to the obtained relationship from the experiment does not exceed 14%, the average uncertainty being less than 8%, which makes it possible to recommend it for practical application in transient flow regime.

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Section: Verification Of the Calculation Methodsmentioning

confidence: 99%

“…The comparison of the conductance values calculated according to (11), (13) and experimental data [4,5] in molecular, transient and viscous flow regimes are presented in Fig. 5 and Fig.…”

Section: Verification Of the Calculation Methodsmentioning

confidence: 99%

“…In viscous flow regime the conductance of the channels 1, 2 is calculated according to the relationships [4,5]…”

Section: Problem Formulationmentioning

confidence: 99%

Section: Problem Formulationmentioning

confidence: 99%

See 2 more Smart Citations

Conductance Calculation Of Slot Channels with Variable Cross Section

Бурмистров¹,

Salikeev²,

Bronshtein³

et al. 2015

Vak Forsch Prax

Self Cite

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“…Salikeev et al [22] calculated conductance coefficients of slot channels formed by cylindrical walls by Monte Carlo method with different wall radius and clearances. Salikeev et al [23] presented the relationship of conductance calculation using three types of slot channels in viscous flow regime at small pressure differences at the ends of the channel. Salikeev et al [24] presented a method for prompt conductance calculation of slot channels with the minimal clearance at a certain point along gas flow direction, and it was used in mathematical models for the pumping process of scroll pumps, claw pumps and Roots pumps.…”

Section: Introductionmentioning

confidence: 99%

Effects of stable clearances on backflow in the variable-pitch screw vacuum pump

Zhang

Yong-ju

Chen

2021

Mechanics & Industry

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Effects of various clearances of variable-pitch screw vacuum pump on gas backflow of internal flow field of the pump cavity is studied. The theoretical tooth surfaces of screw rotor are optimized by radial, normal equidistance modifications, and four types of stable clearances of rotor circumferential, radial, tooth shape and tooth sides are obtained. The backflow calculation model in clearances considering Couette backflow and orifice backflow is improved. The three-dimensional model of variable-pitch screw vacuum pump is designed, and the experimental prototype and test device are developed. The internal backflow of vacuum pump is analyzed by using the commercial software Ansys-Fluent® and the calculation model. The results show that the smaller the clearances, the smaller the backflow and the higher the vacuum degree. Among the four types of clearances, the circumferential clearance plays the primary roles. The backflow is directly proportional to the inlet pressure and rotating speed. Predictions are validated by the experimental data with satisfied agreement.

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