
[Sponsors] 
March 17, 2024, 17:32 
flow through multiple holes in a pipe

#1 
New Member
Abhishek Srivastava
Join Date: Apr 2017
Location: Aveiro, Portugal
Posts: 11
Rep Power: 9 
Dear members,
I want to calculate the relationship between number of holes and their diameters in a circular pipe(d = 10mm and L = 1m) flow arranged horizontally for air intake. I have to maintain equal flow rates through all holes and i know the total flow rate (5 L/min) and the suction pressure (100 Pa). I am using Darcyweisbach equation and flow through jet injection physics to calculate discharge through each hole but i am unable to understand matematically how the equation will form. I know that i'll have to adjust pressure in the pipe in order to maintain constant flow rate for each hole. The goal is to find the equation which can give the number of holes and diameters to have equal flow rates for a given total flow rate and d and L of the main pipe. If someone can guide towards the methidology of the problem, it will be of great help. Regards 

March 17, 2024, 17:52 

#2 
Senior Member
Lucky
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 5,680
Rep Power: 66 
You have to build a flow network, which is just a formal name for a system of equations. You can use an electrical analogue: you have some resistors in series and some in parallel and you need to solve for the current (flow) in each leg.


March 18, 2024, 06:36 

#3 
New Member
Abhishek Srivastava
Join Date: Apr 2017
Location: Aveiro, Portugal
Posts: 11
Rep Power: 9 
@LuckyTran
Thank you for the reponse, I am reading more on the topic of flow networks and how to calculate pressure drop for each leg. However, i am still unable to connect the equation together to change diameter of holes to get equal flow rates. I started with a simple problem of a staright pipe with 2 holes. I calculated the pressure drop in the pipe as per Darcy Weisbach equation, friction factor as per colebrrok equation and air flow through each hole due to drag. I am missing the values of pressure drop in the hole. My guess is to start with an initial value and then force equal flow rates to re alculate the diameters. Please let me know if you have any suggestion. 

March 18, 2024, 06:42 

#4 
New Member
Abhishek Srivastava
Join Date: Apr 2017
Location: Aveiro, Portugal
Posts: 11
Rep Power: 9 
Thank you for the reponse, I am reading more on the topic of flow networks and how to calculate pressure drop for each leg. However, i am still unable to connect the equation together to change diameter of holes to get equal flow rates. I started with a simple problem of a staright pipe with 2 holes. I calculated the pressure drop in the pipe as per Darcy Weisbach equation, friction factor as per colebrrok equation and air flow through each hole due to drag.
I am missing the values of pressure drop in the hole. My guess is to start with an initial value for diameters to calculate air flow through hole and then force equal flow rates to recalculate the diameters. Please let me know if you have any suggestion/papers/examples. 

March 18, 2024, 15:15 

#5 
Senior Member
Lucky
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 5,680
Rep Power: 66 
You're looking for the discharge coefficient of an orifice. Here's a canonical orifice plate as an example.


March 19, 2024, 04:29 

#6 
Senior Member
M
Join Date: Dec 2017
Posts: 645
Rep Power: 12 
This might help too: https://www.google.com/search?client...d+calculations


Tags 
discharge, flow, holes, pipe, pressre distribution 
Thread Tools  Search this Thread 
Display Modes  


Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Intuition for why flow follows convex surfaces  lopp  Main CFD Forum  47  February 1, 2022 13:14 
Issues on the simulation of highspeed compressible flow within turbomachinery  dowlee  OpenFOAM Running, Solving & CFD  11  August 6, 2021 06:40 
hi i have an question for U shape type pipe flow.  jmc1tyzen  FLUENT  1  April 15, 2020 05:35 
Setting boundary conditions for simple pipe flow with flow direction changing in time  Sipher  FLUENT  1  May 4, 2015 20:05 
About Turbulence Intensity (Pipe flow assimilated)  gRomK13  Main CFD Forum  1  July 10, 2009 03:11 