Water tunnel turbulence intensity investigation for micro-hydrokinetic turbine application
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Date
2019-06
Authors
Viknaraj A/L Subramaniam
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Abstract
Water tunnel is used to investigate the hydrodynamic behavior of immersed body in
fluid dynamics study. Water tunnel is essential to provide a controlled condition for
fluid flow research. The operational principle of water tunnel is identical to the wind
tunnel but with different working fluid and higher flow-pumping capacity. Tests such
as flow visualization in wind tunnel is more difficult to be conducted as turbulent flows
in wind dissipate quickly whilst water tunnel is more suitable for such purpose due to
higher fluid viscosity. However, the turbulence in the test section must be less than 10%
or lower in order to produce a valid result. The present work focuses on improving the
design criteria for each components and to maximize the performance of the water
tunnel that was developed previously in terms of turbulence intensity reduction and
improvement in flow uniformity. The design criteria of several primary components are
studied and altered to reduce the turbulence intensity. The modified components were
designed, fabricated and assembled to complete the modified water tunnel. This study
also includes quantitative analysis on the velocity profiles and uniformity of the water
flow at the test section. This is done by collecting data of the velocity at every point in
the cross-section of water flow. That result was then used to plot the uniformity graph
and to calculate the turbulence intensity in the water tunnel test section. The final
turbulence intensity in the test section with the modifications made yielded a minimum
result of 6.77%. The previous design yielded a turbulence intensity percentage of 9.66%
comparatively. Thus, the turbulence intensity in the water tunnel was reduced by 29.92
%.