Tractorsport Flowbench Forum Archive

Posted: **Sun May 13, 2007 10:22 pm**

please help me my thesis defence in 2 month. hehehee
i am using 4pcs 3.2m sq per minutes and 25.5 kpa vaccum. so i need to build a box from MDF where i can
put all of them to become one. how big is the volume of the boxes?

can you please look at (URL:
"Types of Pressure
Taps for Small Bore Orifices Pics" there is two types of taping the
pressure. wich one should i use for your formula?
left one or right?

i will use my flow bench for honda D16 cylinder head. with 75mm piston
diameter. with maximum 300CFM. i'm thinking to use 3" acrylic for adaptor
and reduce it to 2" pipe and placing the orifice at that pipe. are you
agree with that?
how big is the optimum size for the orifice?

thanks a lot.

Posted: **Mon May 14, 2007 6:50 pm**

Placing an orifice in a pipe is not a very good idea, because the pipe directs flow towards the orifice. A 70mm orifice inside a 75mm pipe is not going to flow anything like a 70mm orifice in a very large thin flat metal plate.

An orifice in a thin flat plate with a very large volume of STAGNANT UP STREAM AIR is very predictable.

An orifice in a pipe will change it's flow characteristics as the pressure tapping points are moved around, and any bends or discontinuities in the pipe upstream. There cannot be any flow formula, you just build it and calibrate it. And yours will probably behave considerably differently to someone else's built to the same dimensions.

Orifice in a pipe is only used for industrial processes where some rough sort of flow indication is required, only because it is cheap and convenient. It is NEVER used for accurate laboratory grade flow measurement.

Posted: **Tue May 15, 2007 8:50 pm**

There goes my original design of PVC pipe.

Hello to a new design???
Thanks Tony:D

Tractorsport Flowbench Forum Archive

orifice sizing