Measurements of an elliptic pipe jet

• Main Author: Lam, Felicia Chye Peng
• Other Authors: Chua Leok Poh
• Format: Final Year Project
• Language: English
• Published: 2015
• Subjects: DRNTU::Engineering::Mechanical engineering
• Online Access: http://hdl.handle.net/10356/65727
• Institution: Nanyang Technological University

This study is based on the velocity measurements on an elliptic jet with an aspect ratio (AR) 2:1 (50mm by 25mm). Due to the nature of elliptic jets, they allow wide range of industrial applications and fundamental significance of basic flows in turbulence research. The lack of literature studies in this field provide the motivation for this study. This experiment is conducted on two different kinds of probes; single-wire and cross-wire at stream wise distances of 1 ≤ x⁄D_e ≤38 for both major and minor axes. The velocity measurements are plotted against the normalized local coordinates by the equivalent diameter, D_e of 35.4mm. The jet nozzle’s exit velocity is 24 ± 0.5 m⁄s with Reynolds number at about 54200. This study is segregated into two different parts. The first part of the study is conducted on a single wire probe for mean and RMS (root mean square) velocities along major and minor axes across stream wise distances. The difference in spreading rates led to the unique phenomenon found in elliptic jet known as the axis switching at x = 25D_e. The potential core of the jet is found to end at 4D_e. The mean velocity profile features self-similarity at x = 12D_e and x = 9D_e for major and minor axes respectively. This experiment with 2:1 AR elliptic pipe jet was being compared with the results from the previous final year report and also its counterparts of contoured contraction elliptic nozzle to make the comparisons between the different quantities like axis-switching and self-preservation etc