M. T. Abu Seman ¹, F. Ismail ², H. Yusoff ³, M. A. Ismail ²

Affiliations
1 Department of Mechanical Polytechnic, Seberang Perai, MY
2 School of Mechanical Engineering University, Sains - 11800, MY
3 Faculty of Mechanical Engineering, University Teknologi MARA (Pulau Pinang), MY

Abstract

This paper is devoted to a two-dimensional numerical study of the influence of surface roughness on the cross-flow around a Counter-Rotating Cylinder. The surface roughness consists of irregular notches periodically distributed on the cylinder surface. The roughness was varied using different notch patterns and heights. The roughness patterns were tested on the cylinder. It was investigated approximately using two-dimensional block with average height and different shapes periodically distributed on a smooth cylinder. The influence of the roughness on the drag coefficient, stagnation point pattern and location of separation point was studied numerically over the range of Reynolds numbers 2.0 x 103 < Re < 4.2 x 104 at rotating speed 400 rpm. In the Counter-Rotating Cylinder with roughness, no as well as different observed on drag coefficient prediction compared with previously published. However, the stagnation point and separation point on roughness cylinder is quite difference between a smooth cylinder.

Keywords

Circular Cylinder, Reynolds Number, Rotation Speed, Surface Roughness

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M. A. Ismail ¹, S. H. Mohammad Firdaus ², S. N. Soid ³, M. K. Khalil ⁴, H. Yusoff ²

Affiliations
1 Group Advanced Packaging and SMT, Faculty of Mechanical Engineering, Universiti Sains Malaysia, Pulau Pinang, MY
2 Faculty of Mechanical Engineering, Universiti Teknologi Mara, Pulau Pinang, MY
3 Universiti Kuala Lumpur Malaysian Spanish Institute, Kulim Hi-Tech Park, Kedah, MY
4 School of Material and Mineral Resources Engineering, University Sains Malaysia, Pulau Pinang, MY

Abstract

Heat distribution characteristics e.g. temperature, the local Nusselt number, local heat flux etc., contribute to ice accretion on all critical surfaces of aircraft. The non-uniformity in heat distribution at these surfaces results in low temperatures and runback ice accretion downstream from these surfaces areas. Most of the previous studies merely extracted local temperature or local Nusselt number profiles at certain locations/cross-sectional planes on the surface to describe the uniformity of the temperature, which of two does not represent the overall temperature distribution on the entire surface. This paper proposes using the Coefficient of temperature deviation (Ctem dev), which is obtained using Statistical Quality Control (SQC) and statistical methods, as the measurement of the anti-icing system’s temperature uniformity. The discussion covers the uniformity of the temperature distribution in a nacelle lip, which is produced by Swirl Anti-Icing (SAI) system. This paper also numerically investigates the effects of an SAI system's nozzle length and nozzle rotation angle on the temperature uniformity over several Reynolds numbers (Re) in a D-chamber, ranging between 7.5 x 104 and 4.1 x 105. At Re= 7.58 x 104 and velocity of free stream = 48.75 m/s, Ctem dev decreases by 13.7% as the Nozzle Direction Angle (NRA) changes from 0⁰ to 13⁰, which indicates that changing nozzle direction significantly improves the uniformity of the temperature distribution on a nacelle lip surface. However, according to the numerical results, Ctem dev is insensitive to nozzle length. The results also show that the uniformity of the temperature distribution improves as the Re increases, for NRA values of both 0⁰ and 13⁰.

Keywords

Anti-Icing, CFD, Coefficient of Temperature Deviation, Nusselt Number, Reynolds Number, Temperature Uniformity

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