Experimental Investigation of the Continual Jet

Sudarshan Shamsundar Boob

Master's thesis

Abstract:

This thesis work primarily focusses on the study of the structure and development of the free jet generated though the round air jet nozzle. It also involves the study of the velocity fields generated by round jet at the nozzle exit velocity 5.67 m/s and with corresponding Reynolds number of 3070.The investigation was carried out in 2D (stereo PIV) and 3D (Tomo PIV). The scope of the study was further extended to understand the characteristics of all three velocity components in the developing shear layer and deriving the pressure fields over the space using the available velocity field data. Pulsed laser sheets were aligned such that it illuminates the centreline plane of the jet. The set-up was calibrated to translate the resulting pixel displacements into X, Y, and Z velocity components. The measurement was done with varying the laser power and varying the laser pulse time i.e. delay time. For measurement of the Tomo PIV the volume optics were used also volume self-calibration were carried out. The tracer particles used in the experiment were generated from the vegetable oil and compressed air was used for providing the necessary acceleratory movement to the particles. The result helped to study the different structures and development of the free jet along its centreline axis direction. The velocity range over entire field and pressure variations along the streamline axis are discussed. The maximum particle velocity was found to be 25 m/s in the jet core.

Abstract:

This thesis work primarily focusses on the study of the structure and development of the free jet generated though the round air jet nozzle. It also involves the study of the velocity fields generated by round jet at the nozzle exit velocity 5.67 m/s and with corresponding Reynolds number of 3070.The investigation was carried out in 2D (stereo PIV) and 3D (Tomo PIV). The scope of the study was further extended to understand the characteristics of all three velocity components in the developing shear layer and deriving the pressure fields over the space using the available velocity field data. Pulsed laser sheets were aligned such that it illuminates the centreline plane of the jet. The set-up was calibrated to translate the resulting pixel displacements into X, Y, and Z velocity components. The measurement was done with varying the laser power and varying the laser pulse time i.e. delay time. For measurement of the Tomo PIV the volume optics were used also volume self-calibration were carried out. The tracer particles used in the experiment were generated from the vegetable oil and compressed air was used for providing the necessary acceleratory movement to the particles. The result helped to study the different structures and development of the free jet along its centreline axis direction. The velocity range over entire field and pressure variations along the streamline axis are discussed. The maximum particle velocity was found to be 25 m/s in the jet core.

Keywords

Development of free jet, nozzle geometry, Tomo-PIV, stereo PIV, continual jet, vorticity, pressure distribution, tracer particle, PIV errror, PIV uncertainity quantification

Language used: English

Date on which the thesis was submitted / produced: 3. 5. 2019

Thesis defence

• Supervisor: Ing. Petra Dančová, Ph.D.

Technical University of Liberec

Faculty of Mechanical Engineering

Master programme / field:
Mechanical Engineering / Machines and Equipment Design