THERMAL-FLUID FLOW TRANSPORT PHENOMENA IN AN AXIALLY ROTATING FLOW PASSAGE WITH TWIN CONCENTRIC ORIFICES

摘要

This paper investigates the secondary flow and heat transfer characteristics in an axially rotating passage in the presence of twin concentric orifices. Emphasis is placed on the effects of pipe rotation and orifice configuration on the flow and thermal fields, i.e., both the formation of vena contracta and the heat-transfer performance behind each orifice. The governing equations are discretized by means of a finite-difference technique and are numerically solved for the distributions of velocity vector and fluid temperature subject to constant wall temperature and uniform inlet velocity and fluid temperature. It is found that: (ⅰ) for a laminar flow through twin concentric orifices in a pipe, axial rotation causes the vena contracta in the orifice to stretch, resulting in an amplification of heat-transfer performance in the downstream region behind the rear orifice, and (ⅱ) the local heat-transfer performance between the twin orifices is affected by an orifice interval, even if the orifice height and pipe rotation rate are the same. Results may find applications in automotive and rotating hydraulic transmission lines.