M. Sundararaj ¹, S. Elangovan ¹

Affiliations
1 Department of Aeronautical Engineering, Bharath University, Chennai-600 073, IN

Abstract

A Computational study has been carried out to understand jet flow development from plain and grooved rectangular nozzles of aspect ratio 2:1. Grooves of square cross section of side 4mm and axial length 5mm were introduced at the exit of the nozzle in three different orientations as (i) minor-axis, (ii) major-axis and, (iii) in both minor and major axes. The computational studies were carried out using computational software ANSYS CFX for a nominal jet exit velocity of 20m/s. Velocity distribution along the axis of the jet is observed from computational results and compared with the available experimental results. Grooves seem to have very negligible effect on the near field region but significantly influence the jet decay in the far field.

Keywords

Passive Control, Jet Mixing Enhancement, Rectangular Jet and Center Line Velocity Decay

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M. Sundararaj ¹, S. Elangovan ¹, B. T. N. Sridhar ²

Affiliations
1 Department of Aeronautical Engineering, Bharath University, Agaram Then Road, Selaiyur, Chennai, IN
2 Department of Aerospace Engineering, Madras Institute of Technology Campus, Anna University, Chromepet, Chennai, IN

Abstract

The Effect of freestream velocity and Ellipticity ratio on the similarity distribution of the static pressure along the wake axis of the elliptic cones is presented. A cone of elliptic cross section produces separated flow at the downstream of its base. Within the separated region the flow is observed to be opposite (reverse) to the main outer flow. To obtain the length of reverse flow region, magnitude and location of maximum reverse velocity and re attachment point knowledge of pressure distribution behind a body is essential. Experiments were carried out for three different test section freestream velocities 6m/s, 15m/s and 25 m/s (Reynolds numbers 0.16 x 105, 0.4 x 105 and 0.667 x 105 based on cone effective diameter respectively). Ellipticity ratio 1 and 3 with constant fineness and bluntness ratio of 2.75 and 0.049 respectively were considered for the experiments. A Digital Sensor Array -DSA was used for static pressure measurements. The pressure sensor has the capability of 1 PSI differential pressure range with +/- 0.12% full-scale accuracy. Good similarity in wake axis static pressure distribution is noted for different freestream velocity behind a circular cone. But, Similarity in pressure distribution is not observed along the wake axis of an elliptic cone at tested lower freestream velocity (6 m/s).

Keywords

Elliptic Cone, Pressure Coefficient And Similarity Parameter, Wake Pressure

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M. Sundararaj ¹, C. Yuvaraj ¹, S. Gopinath ¹, S. Elangovan ¹

Affiliations
1 Department of Aeronautical Engineering, Bharath University, Agaram then road, Selaiyur, Chennai, Tamil Nadu, IN

Abstract

Suddenly expanded flows find application in various engineering devices. The flow in the sudden expansion region is found to be affected by various factors. Passive control methods like protruding ribs are found to be very effective in the control of suddenly expanding flows. In the present study the effect of geometry of ribs on the flow characteristics is investigated computationally. The rib geometries studied are rectangular of two aspect ratios, circular, semicircular and triangular. The computational results show that rectangular rib of aspect ratio 3 significantly reduced the base pressure. The results compare very well with experimental results.

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R. Saravanakumar ¹, S. Sivalingam ¹, S. Elangovan ²

Affiliations
1 Department of Mechanical Engineering, KPR Institute of Engineering and Technology, Coimbatore - 641407, Tamil Nadu, IN
2 Environmental Division, Public Works Department, Coimbatore Division, Coimbatore, Tamil Nadu, IN

Abstract

Background/Objectives: The prime objective of this work is to study the condition and quality of the air in Coimbatore city by measuring Air Quality Index (AQI) and to compare the measured values with standard values. This work also examines the variation of ambient air quality with various climatic conditions. Methods/Statistical Analysis: The quality of air was determined based on National Ambient Air Quality Standards (NAAQS). This was carried out based on measuring four major air pollutants such as PM10, PM2.5, SO2 and NO2 at different climate conditions during January 2015 to December 2015. Respirable Dust Sampler (RDS) and Fine Particulate Sampler were used to determine PM10 and PM2.5 respectively. Findings: The present work shows its significance because there is no such data available for researchers for reference. Industrial (foundry units) and automobile emissions are the major pollution source which determines the quality of ambient air in the city. Among the different climatic conditions, summer exhibits more pollution level in the air while monsoon exhibits less pollution level. Results also reveals that the Industrial area experiencing more pollutants followed by commercial and residential areas. As per the AQI category, all locations are coming under moderate category except industrial location which requires stringent control measures to reduce the particulate matters in the air. Applications: Since no data is available for the Air Quality Index study of the region, this can be taken as a reference for future study.

Keywords

Air Quality Index, Automobile Emission, Dust sampler, Pollution Level and Particulate Matter.

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