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Rasoul Daneshfaraz

Rasoul Daneshfaraz

Academic rank: Professor
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Education: PhD.
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Faculty: 1
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Research

Title
Numerical investigation on the effect of sudden contraction on flow behavior in a 90-degree bend
Type
JournalPaper
Keywords
numerical simulation ،pressure drop ،relative pressure drop
Year
2018
Journal KSCE Journal of Civil Engineering
DOI
Researchers Rasoul Daneshfaraz ، Ali Rezazadeh JOUDI ، JOHN ABRAHAM

Abstract

Here we investigate fluid flow in 90-degree bends with and without orifice-like constrictions. The results of flow in non-constricted bends were compared with experimental results for similar Reynolds numbers and found to be in good agreement. Calculations were then carried out for various Reynolds numbers in the laminar and turbulent regimes. In addition, constrictions up to a 60% blockage were incorporated. The present study shows that the Reynolds number and the presence of an orifice-like constriction affects the velocity profile and the pressure distribution. The results indicate that if a sudden contraction is encountered, the peak velocity is larger and the flow is more predisposed to the outer wall than it otherwise would be. In addition, a sudden contraction increases the pressure loss compared to the constant-area bend and it affects the pressure distribution throughout the entire bend. This paper provides a means to predict pressure losses (similar to minor loss coefficients) in rounded bends in the presence or absence of constrictions. Such information is important to practicing engineers for designing fluid-flow conveyance systems. The behavior of the fluid is shown to be connected to the constriction and is also affected by the Reynolds number.