Showing posts with label Aerodynamics-CFD. Show all posts

DISCLAIMER: Remember all of the following are just general guidelines and should not be relied on as a precise source for information.
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Key points to remember:

  • Pressure loss: As fluid flows through a pipe, it experiences pressure loss due to friction. Longer pipes and higher flow rates generally lead to greater pressure loss.
  • Noise: High flow velocities can cause noise in pipes. Minimizing noise often involves using larger pipes or reducing flow rates.
  • Safety: Exceeding the pressure rating of a pipe can be dangerous. Always consult with a qualified professional if you're unsure about the safe operating pressures for your piping system.


NOMOGRAPH: FLOW RATE vs PIPE SIZE


How to use a Nomograph:
  1. You should size your pipe so that your flow velocity stays in the green or yellow range.
  2. The green range is safest, most efficient and will produce little to no noise. 
  3. Flow velocities in the yellow range may be noisy and have additional back pressure. 
  4. Flow velocities in red are not recommended because of the risk of hydraulic shock and pipe/fitting/joint & pump failure.
  5. Find your flow in the first column (GPM) and then select the pipe size you want in the second column (pipe, ID in inches.) 
  6. Draw a straight line between them all the way to the last column. If the line ends up in the green you are good. If it ends in the yellow or red, increase the pipe size until your line ends in the green (best) or yellow (just okay) area.
NOTE: 
These figures are for straight pipe only! The effect of putting direction changes in will compound the back pressure even more and could even result in failure of the system or burning up the pump.
You will never be hurt by going to a bigger pipe and will gain by using less electricity due to a more efficient system which may offset the initial price difference for the larger pipe.



PVC material chemical resistance chart wrt Temperature



References:
https://cdn.flexpvc.com/graphics/head-loss-nomograph-chart.gif
https://flexpvc.com/docs/chemical-ratings.png
https://flexpvc.com/docs/ChemicalRatingsChartForPVCPlastics.pdf
https://flexpvc.com/Reference/FeetOfHeadPressureToPSIChart.pdf
https://flexpvc.com/Reference/PVC-Pipe-Weight-Per-Foot.shtml
https://flexpvc.com/Reference/WaterFlowBasedOnPipeSize.shtml
https://hy-techroofdrains.com/water-flow-through-a-pipe/

Authors: Karanbir Singh Sidhu, Ankit Goyal
Publication Date: 05-11-2015 

Abstract:
The geometry of a pump intake structure is responsible for providing an efficient water supply to a series of pumps; failure of which causes undesirable-turbulent flow patterns, flow separation; which further leads to generation of unacceptably high magnitudes of swirl, undesirable cavitation of the impeller in conjunction with excessive mechanical vibrations in the pumps. 

The flow characteristics in pump intakes having multiple pump installations is involved, which consequentially demands for an empirical, as well as, a numerical methodology for the design of its intake geometry. The numerical study carried out in this paper aims at optimizing the overall fluid flow in a pump intake by the use of a commercially available CFD code. The test cases pertain to an intake with, 4 identical pumps working at duty point at the lowest water level (LWL), with a severely non-uniform and turbulent flow resulting due to the inherent constraints imposed by the intake geometry, arising due to site specific conditions. A total of three test cases are discussed, two of them have blocking arrangements aimed to optimize the fluid flow behavior. The flow is successfully optimized and a control over the flow is introduced by the unique application of the well-established fluid phenomena- “wall attachment” or the “Coanda effect” in the design of a curved surface blocking arrangement used in the ultimate case.


DOI:  http://dx.doi.org/10.17577/IJERTV4IS110129


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