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Slip ratio (or velocity ratio) in gas–liquid (two-phase) flow, is defined as the ratio of the velocity of the gas phase to the velocity of the liquid phase.〔G.F. Hewitt, G.L. Shires, Y.V.Polezhaev (editors), "International Encyclopedia of Heat and Mass Transfer," CRC Press, 1997.〕 In the homogeneous model of two-phase flow, the slip ratio is by definition assumed to be unity (no slip). It is however experimentally observed that the velocity of the gas and liquid phases can be significantly different, depending on the flow pattern (e.g., plug flow, annular flow, bubble flow, stratified flow, slug flow, churn flow). The models that account for the existence of the slip are called "separated flow models." The following identities can be written using the interrelated definitions: : where: * S – slip ratio, dimensionless * indices G and L refer to the gas and the liquid phase, respectively * u – velocity, m/s * U – superficial velocity, m/s * ε – void fraction, dimensionless * ρ – density of a phase, kg/m3 * x – steam quality, dimensionless. == Correlations for the slip ratio == There are a number of correlations for slip ratio. For homogeneous flow, S = 1 (i.e., there is no slip). The Chisholm correlation〔D. Chisholm, "Two-Phase Flow in Pipelines and Heat Exchangers", Longman Higher Education, 1983. ISBN 0-7114-5748-4〕〔John R. Thome, "Wolverine Heat Transfer Engineering Data book III," Wolverine Tube Inc, 2004, Chapter 17 ().〕 is: The Chisholm correlation is based on application of the simple annular flow model and equates the frictional pressure drops in the liquid and the gas phase. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Slip ratio (gas–liquid flow)」の詳細全文を読む スポンサード リンク
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