Design of an Optical Box for Laser Doppler Anemometer Measurements

• Main Author: Long Zainudin, Long Zulkamaen
• Format: Final Year Project
• Language: English
• Published: Universiti Teknologi PETRONAS 2011
• Subjects: TJ Mechanical engineering and machinery
• Online Access: http://utpedia.utp.edu.my/10283/1/2011%20Bachelor%20-%20Design%20Of%20An%20Optical%20Box%20For%20Laser%20Doppler%20Anemometer%20Measurements.pdf; http://utpedia.utp.edu.my/10283/
• Institution: Universiti Teknologi Petronas

This report is about Design of an optical box for Laser Doppler Anemometer measurements and fluid velocity measurement using Laser Doppler Anemometer. Laser Doppler Anemometer uses a beam of light from laser to measure velocity of fluid flows. The objective of the project is to design a module of laser Doppler anemometer that can simplifY mathematical derivation for refraction correction of velocity measurement and to run a test on the test section to obtain transversal measurement of fluid velocity very close to the pipe wall. The main factor to be considered in the experiment is the refractive index of the elements used. The design will include acrylic pipe tube with '+' cross slit on the pipe wall, Teflon film to cover the cross slit, a gear, and a connecting device to connect the test section to the pipe section. The pipe needs to be rotatable so .that it can be used to measure the velocity of fluid flow at different points. The experiments will be conducted using LDA laser which will pass through different types of medium before reaching the fluid interface. Mathematical derivation can be simplified by having the optical box and a cross slit on the pipe wall, which will reduce refraction as the beams goes through the box, fluid inside the box and straight to the fluid inside the pipe by eliminating the effect of pipe curvature. For that, refraction needs to be as small as possible in such way that angle of incident is almost the same with angle of refraction (zero refraction), where the refractive index of the pipe wall and the Teflon film covering the slit are similar to the fluid being tested.