The fluid mechanics of transition sections between ducts
The fluid mechanics of transition sections between ducts
A considerable number of transition geometries between ducts of varying cross-sectional area and/or shape are studied. In all cases, the analysis is based on straight-line generators along the transitions. Two area distributors are considered: firstly, area normal to the end duct centre lines; and secondly, area perpendicular to the transition centre line, in transitions with the inlet and outlet duct centre line offset. For the first case, the area variation is of a quadratic form along the transitions, however, for the second case, the variation is more complicated. A new design of some particular transitions, using curved walls to provide constant cross-sectional area along such transitions, is discussed. Experimental results are presented for the pressure losses in transition between square and rectangular ducts of the same cross-sectional area. These transitions include divergent-convergent, constant-area and sudden transitions. Effects of direction of flow, inlet conditions and surface roughness are examined. Sudden transitions have the highest pressure losses; however, the lowest pressure losses are obtained in the constant-area transitions. In all types of the transitions tested the pressure loss is a function of the aspect ratio at the rectangular end; where it is higher at lower aspect ratios. Numerical methods are introduced to solve the two-dimensional boundary-layer equations. An attempt is made to use this technique in predicting the performance of such transition ducts.
University of Southampton
1986
Dekam, Elhadi Ibrahim
(1986)
The fluid mechanics of transition sections between ducts.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
A considerable number of transition geometries between ducts of varying cross-sectional area and/or shape are studied. In all cases, the analysis is based on straight-line generators along the transitions. Two area distributors are considered: firstly, area normal to the end duct centre lines; and secondly, area perpendicular to the transition centre line, in transitions with the inlet and outlet duct centre line offset. For the first case, the area variation is of a quadratic form along the transitions, however, for the second case, the variation is more complicated. A new design of some particular transitions, using curved walls to provide constant cross-sectional area along such transitions, is discussed. Experimental results are presented for the pressure losses in transition between square and rectangular ducts of the same cross-sectional area. These transitions include divergent-convergent, constant-area and sudden transitions. Effects of direction of flow, inlet conditions and surface roughness are examined. Sudden transitions have the highest pressure losses; however, the lowest pressure losses are obtained in the constant-area transitions. In all types of the transitions tested the pressure loss is a function of the aspect ratio at the rectangular end; where it is higher at lower aspect ratios. Numerical methods are introduced to solve the two-dimensional boundary-layer equations. An attempt is made to use this technique in predicting the performance of such transition ducts.
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Published date: 1986
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Local EPrints ID: 460806
URI: http://eprints.soton.ac.uk/id/eprint/460806
PURE UUID: c0cded5f-8721-4a03-b121-9aee634382fe
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Date deposited: 04 Jul 2022 18:30
Last modified: 04 Jul 2022 18:30
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Author:
Elhadi Ibrahim Dekam
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