RegimeMaps_web - ENU 4134 – Regime Maps D Schubring...

Info iconThis preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: ENU 4134 – Regime Maps D. Schubring October 2, 2009 Empirical Analysis of Two-Phase Fluid Mechanics Motivation: for many applications, the analytical two-phase parameters ( { α } , S , etc.) from the first block are hard/impossible to evaluate. It is often easier to develop empirical models based on a particular flow regime, in which certain effects are expected to be dominant. Such an approach proceeds in two stages: (1) identify or model or otherwise determine the flow regime and (2) apply regime-specific models/correlations to predict quantities of interest ( dP / dz , etc.). This block includes 7 class periods. However, it’s wrapped around Exam 1 and (yet another) UF holiday, so it will take 3 weeks. Empirical Analysis of Two-Phase Fluid Mechanics Schedule I Flow Regime Maps – 1 I Annular Flow – 1.5 I Bubbly Flow – 0.75 I Other flow regimes (intermittent and horizontal) – 0.75 I Counter-current two-phase flow – 0.5 I Pressure drop models – 2.5 The emphasis on bubbly flow is due to its importance for nuclear applications. The emphasis on annular flow is due to its importance (steam generators, BWR’s) and to Project #1. Flow Regime Maps I Outline of horizontal and vertical flow regimes seen in these maps. I Mapping coordinates. I Example horizontal and vertical maps. I Vertical flow map of Taitel et al. – theoretically determined transitions. I Flows with phase change and concluding remarks. Horizontal vs. Vertical Flow In horizontal flow, gravity acts perpendicular to the direction of flow As a result, parameters in horizontal flow (local velocity, void fraction, wall shear, etc., etc.) are often functions of θ . In vertical flow, gravity acts parallel to the direction of flow. This adds an additional “source” of pressure drop ( ρ m g ) and emphasizes the importance of { α } , even when a regime-based model is used. Gravity also leads to strongly time-varying parameters ( e.g. , liquid that has negative velocities at times in slug flow). Flow Regimes in Vertical Flow – Hewitt and Hall Taylor Bubbly, slug, churn, annular Flow Regimes in Horizontal Flow – Barnea Regime Identification Subjective – clear tube and see what’s there....
View Full Document

This note was uploaded on 07/14/2011 for the course ENU 4133 taught by Professor Schubring during the Spring '11 term at University of Florida.

Page1 / 28

RegimeMaps_web - ENU 4134 – Regime Maps D Schubring...

This preview shows document pages 1 - 9. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online