Orifice plate and Venturi tube calculator redesigned

[admin]

Orifice plate and Classical Venturi tube calculator are redesigned to better comply with ISO 5167:2003.

All three calculators for fluid flow measurement by means of pressure differential devices inserted in circular cross-section conduits running full - Orifice plates, nozzles and Venturi nozzles and classical Venturi tubes are now in compliance with ISO 5167:2003.

Limits of use according to ISO 5167 are now applied and calculators can be used for compressible flow also.

Calculators can be found on:
http://www.pipeflowcalculations.com/orifice/
http://www.pipeflowcalculations.com/venturi/
http://www.pipeflowcalculations.com/nozzle/

Theory used in calculators can be found at:
http://www.pipeflowcalculations.com/pip ... ifices.php

[PCX]

Administrator,

is there a way to disable the compliance with ISO 5167:2003 in the calculator?

I need to do calculations for a university project that do not comply with this limit.

thanks in advance

[admin]

No, I am working on new ones that can be used to illustrate Venturi effect and discharge through orifice

[Roberto]

Hi,
I was wondering about your software, I was looking for something like it from years... but something makes me thinking: It looks wrong that changing the viscosity of the fluid from a light oil to a thicker one, like from 10 to 100 cSt (or mm^2/S) the flowing liters passing by the orifice increases instead to decrease.
Can you explain if I'm wrong... or not?
Thanks
Roberto

[admin]

Roberto,

It seams like it is wrong, but if you look at the equation for flow rate through orifice, you can see that only in terms of discharge coefficient C, through Reynolds number, viscosity is treated. Also in equation for discharge coefficient, Reynolds number is in denominator, which means if viscosity is higher, Reynolds number is lower and coefficient of discharge is also higher which results in higher flow rate for the same pressure difference in front and after the orifice.

That is mathematical solution and confirmation for this problem, but what about physical? I would say that that due to higher viscosity ,vena contracta effect is smaller and the contraction of flow stream after the orifice is not as big as it is with less viscous fluid.

As contraction of flow stream after the orifice is smaller, flow cross section is bigger and flow rate is also higher.

Here is the theory from ISO for orifice flow:
http://www.pipeflowcalculations.com/pip ... ifices.php

[admin]

No, I am working on new ones that can be used to illustrate Venturi effect and discharge through orifice

It has been changed so now you can select if you want to comply with ISO or not, checking or unchecking within the application. By default, compliance with ISO is disabled as required.