Experimental study of pressure drop reduction on in-line tube bundle using passive control

¹ Laboratoire d’aérohydrodynamique navale, Département de génie maritime, Mechanical Engineering Faculty, 31000 USTO Oran, Algeria
² Laboratoire d’aéronautique et systèmes propulsifs, Département de Génie Mécanique, Mechanical Engineering Faculty, 31000 USTO Oran, Algeria

^a Corresponding author: ladjedelomar@yahoo.com

Received: 3 July 2012
Accepted: 30 June 2013

Abstract

In the present paper an experimental investigation of drag reduction on in-line tube bundles with a configuration of seven by seven with a pitch ratio of 1.44 has been performed. Two longitudinal grooves are placed on the external surface of the circular cylinders as a passive control. The experiment is carried out using a subsonic wind tunnel. The pressure distributions for various azimuthal angles along the tubes are measured using a multi-channel differential pressure. Drag forces are also determined using a combined wire-strain gauge balance. The pressure drops are deduced from the resulting drag forces. The results obtained show an unexpected reduction in the pressure drop for the tube bundles. A reduction of 36.5% in the pressure drop for a Reynolds number of 1.33 × 10⁴ is found compared to the configuration without grooves. Some correlations for the pressure drop are proposed.