Pressure Drop Study of a Micro-jet Device - Steve Tian Huang
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This study was to illustrate the velocity and pressure changes in a device designed by Thomas Keenan, Ph.D., and Prof. Albert Folch. Flow comes in the left side (the side channel), down through the microjets (4 are shown), and into a pool. They are interested in the shear rate on cells attached to the bottom of the pool. The work presented here is preliminary and qualitative. |
The pressure in the side channel decreases down the channel because of friction but also because the velocity is decreasing. Thus the pressure profile is slightly curved. |
Approximations to the pressure drops were calculated using correlations from the literature, ignoring the 2D and 3D effects. Flow in a square channel is governed by:
(Perry's Chemical Engineers' Handbook, p. 6-12), while flow in a rectangular channel is governed by a similar equation.
The pressure drops in the side channel were 0.01 psi and in the microjet were 0.1 psi. |
Pressure drops due to the expansion and contraction were estimated using calculations for expansions and contractions that were straight (the device here has turns, too). The equations used were for the expansion:
and for the contraction:
Typical values were 1.7e-3 psi. |
Streamlines in 2D version |
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