flow bench program
Discussion
coincidentally I bought flowsoft excel for my bench 2 days ago:
http://www.cavanaughracing.com/flowsoftexcel.html
this is designed specifically for flowbenches running a PTS digital manometer (which mine does), but even if yours doesn't it should give you a great idea of what is possible and for only 50 US dollars might save you a load of time.
http://www.cavanaughracing.com/flowsoftexcel.html
this is designed specifically for flowbenches running a PTS digital manometer (which mine does), but even if yours doesn't it should give you a great idea of what is possible and for only 50 US dollars might save you a load of time.
Hiya
I wrote an html based javascript to do the maths for my floating depression flow bench I attach the code here, to use it you need to adjust variable C if you do not agree with the 0.596 CD I use. If you copy and paste it in a text editor such as Notepad and save it as a .html or .htm extension it should fire up in a web browser, sometimes you have to tell the browser to run scripts. The script is not well written but I am self taught and it does work. It takes into account temp/pressure/humidity and assumes isentropic flow conditions. I am not going to enter into the ins and outs of the maths, suffice it to say it has been used by at least three students as part of their theses to gain Engineering degrees. If you use the code elsewhere please be polite enough to say it is written by Peter Burgess'. I hope you get as much enjoyment from flow benching as I have for the last 28 years!
Peter
<html>
<head>
<title>Flowbench JavaScript</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<script>
<!--
var A = prompt("Enter valve diameter in millimetres","Valve diameter");
var X = prompt("Enter the reading on manometer X in millimetres", "Reading on Manometer X in millimetres");
var Y = prompt("Enter the reading on manometer Y in millimetres", "Reading on Manometer Y in millimetres");
var T = prompt("Enter the temperature reading in degrees centigrade", "Temperature in degrees C");
var P = prompt("Enter the atmospheric pressure reading in millibars", "Atmospheric pressure in millibars");
var V = prompt("Enter the vapour pressure of water at test temperature T centigrade", "Vapour pressure in N/m2");
var H = prompt("Enter the relative humidity as a decimal pointage", "Relative Humidity");
var O = prompt ("Enter the orifice diameter in millimetres","Orifice diameter in millimetres");
var O = eval(O);
var O = O/2000;
var O = eval(O);
var O = Math.pow(O,2);
var O = eval(O);
var O = 3.1415927 * O;
var O = eval(O);
var A = eval(A);
var X = eval(X);
var Y = eval(Y);
var T = eval(T);
var P = eval(P);
var V = eval(V);
var H = eval(H);
var X = X * 9.81;
var Y = Y * 9.81;
var Pr = P * 100;
var Pr = eval(Pr);
var dP = Pr-Y-X;
var dP = eval(dP);
var ndP = (dP * 1.404);
var ndP = eval(ndP);
var ndP = (X / ndP);
var ndP = eval(ndP);
var S = 1-(0.410072 * ndP);
var S = eval(S);
var Q = Pr-Y;
var Q = eval(Q);
var T = (T + 273);
var T = eval(T);
var K = (.378 * V * H);
var K = eval(K);
var Zz = (Q - K);
var Zz = eval(Zz);
var R = (Zz / T);
var R = eval(R);
var d = (R * 0.003482);
var d = eval(d);
var A = (A/2);
var A = eval(A);
var A = (A/1000);
var A = eval(A);
var A = Math.pow(A,2);
var A = eval(A);
var A =(A * 3.1415927);
var A = eval(A);
var C = 0.596;
var C = eval(C);
var B = (2 * d * X);
var B = eval(B);
var B = Math.pow(B,0.5);
var B = eval(B);
var M = (O * C * S * B);
var M = eval(M);
var V = (M / 1.225);
var V = eval(V);
var Z = ( 6229.35 / Y);
var Z = eval(Z);
var Z = Math.pow(Z,0.5);
var Z = eval(Z);
var F = (V * Z * 2118.8802);
var F = eval(F);
var F = F * 100;
var F = eval(F);
var F = Math.round(F) / 100;
var F = eval(F);
var E = (0.000789 / A);
var E = eval(E);
var E = (E * 0.62);
var E = eval(E);
var J = ( X / Y);
var J = eval(J);
var J = Math.pow(J,0.5);
var J = eval(J);
var Cd = (J * E);
var Cd = Cd * 100;
var Cd = eval(Cd);
var Cd = Math.round(Cd) / 100;
var Cd = eval(Cd);
var F = F * 100;
var F = eval(F);
var F = Math.round(F) / 100;
var F = eval(F);
var Cot = F * 0.632;
var Cot = eval(Cot);
var Cot = Cot * 100;
var Cot = eval(Cot);
var Cot = Math.round(Cot)/100;
var Coe = F * 0.775;
var Coe = eval(Coe);
var Coe = Coe * 100;
var Coe = eval(Coe);
var Coe = Math.round(Coe)/100;
var Cof = F * 1.058;
var Cof = eval(Cof);
var Cof = Cof * 100;
var Cof = eval(Cof);
var Cof = Math.round(Cof)/100;
function MM_goToURL() { //v3.0
var i, args=MM_goToURL.arguments; document.MM_returnValue = false;
for (i=0; i<(args.length-1); i+=2) eval(args[i]+".location='"+args[i+1]+"'");
}
//-->
</script>
</head>
<body bgcolor="#000066" text="#CCCCCC" link="#99FFFF" oncontextmenu="return false">
<div id="Layer3" style="position:absolute; width:200px; height:115px; z-index:4; left: 18px; top: 286px"><img src="img0.gif" width="468" height="114"></div>
<script>
document.write("The airflow is "+ F + " c.f.m. at 25 inches H2O.");
document.write("<BR>The airflow is "+ Cot + " c.f.m. at 10 inches H2O.");
document.write("<BR>The airflow is "+ Coe +" c.f.m. at 15 inches H2O.");
document.write("<BR>The airflow is "+ Cof + " c.f.m. at 28 inches H2O.");
document.write("<BR>The coefficient of discharge is " + Cd );
</script>
<div id="Layer1" style="position:absolute; width:200px; height:45px; z-index:3; left: 13px; top: 176px">
<form name="form1" >
<input type="button" name="Button2" value="Click here to evaluate more flow figures" onClick="MM_goToURL('parent','flowmaths.html');return document.MM_returnValue">
</form>
</div>
<div id="Layer4" style="position:absolute; width:475px; height:35px; z-index:5; left: 23px; top: 411px">
</div>
</body>
</html>
I wrote an html based javascript to do the maths for my floating depression flow bench I attach the code here, to use it you need to adjust variable C if you do not agree with the 0.596 CD I use. If you copy and paste it in a text editor such as Notepad and save it as a .html or .htm extension it should fire up in a web browser, sometimes you have to tell the browser to run scripts. The script is not well written but I am self taught and it does work. It takes into account temp/pressure/humidity and assumes isentropic flow conditions. I am not going to enter into the ins and outs of the maths, suffice it to say it has been used by at least three students as part of their theses to gain Engineering degrees. If you use the code elsewhere please be polite enough to say it is written by Peter Burgess'. I hope you get as much enjoyment from flow benching as I have for the last 28 years!
Peter
<html>
<head>
<title>Flowbench JavaScript</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<script>
<!--
var A = prompt("Enter valve diameter in millimetres","Valve diameter");
var X = prompt("Enter the reading on manometer X in millimetres", "Reading on Manometer X in millimetres");
var Y = prompt("Enter the reading on manometer Y in millimetres", "Reading on Manometer Y in millimetres");
var T = prompt("Enter the temperature reading in degrees centigrade", "Temperature in degrees C");
var P = prompt("Enter the atmospheric pressure reading in millibars", "Atmospheric pressure in millibars");
var V = prompt("Enter the vapour pressure of water at test temperature T centigrade", "Vapour pressure in N/m2");
var H = prompt("Enter the relative humidity as a decimal pointage", "Relative Humidity");
var O = prompt ("Enter the orifice diameter in millimetres","Orifice diameter in millimetres");
var O = eval(O);
var O = O/2000;
var O = eval(O);
var O = Math.pow(O,2);
var O = eval(O);
var O = 3.1415927 * O;
var O = eval(O);
var A = eval(A);
var X = eval(X);
var Y = eval(Y);
var T = eval(T);
var P = eval(P);
var V = eval(V);
var H = eval(H);
var X = X * 9.81;
var Y = Y * 9.81;
var Pr = P * 100;
var Pr = eval(Pr);
var dP = Pr-Y-X;
var dP = eval(dP);
var ndP = (dP * 1.404);
var ndP = eval(ndP);
var ndP = (X / ndP);
var ndP = eval(ndP);
var S = 1-(0.410072 * ndP);
var S = eval(S);
var Q = Pr-Y;
var Q = eval(Q);
var T = (T + 273);
var T = eval(T);
var K = (.378 * V * H);
var K = eval(K);
var Zz = (Q - K);
var Zz = eval(Zz);
var R = (Zz / T);
var R = eval(R);
var d = (R * 0.003482);
var d = eval(d);
var A = (A/2);
var A = eval(A);
var A = (A/1000);
var A = eval(A);
var A = Math.pow(A,2);
var A = eval(A);
var A =(A * 3.1415927);
var A = eval(A);
var C = 0.596;
var C = eval(C);
var B = (2 * d * X);
var B = eval(B);
var B = Math.pow(B,0.5);
var B = eval(B);
var M = (O * C * S * B);
var M = eval(M);
var V = (M / 1.225);
var V = eval(V);
var Z = ( 6229.35 / Y);
var Z = eval(Z);
var Z = Math.pow(Z,0.5);
var Z = eval(Z);
var F = (V * Z * 2118.8802);
var F = eval(F);
var F = F * 100;
var F = eval(F);
var F = Math.round(F) / 100;
var F = eval(F);
var E = (0.000789 / A);
var E = eval(E);
var E = (E * 0.62);
var E = eval(E);
var J = ( X / Y);
var J = eval(J);
var J = Math.pow(J,0.5);
var J = eval(J);
var Cd = (J * E);
var Cd = Cd * 100;
var Cd = eval(Cd);
var Cd = Math.round(Cd) / 100;
var Cd = eval(Cd);
var F = F * 100;
var F = eval(F);
var F = Math.round(F) / 100;
var F = eval(F);
var Cot = F * 0.632;
var Cot = eval(Cot);
var Cot = Cot * 100;
var Cot = eval(Cot);
var Cot = Math.round(Cot)/100;
var Coe = F * 0.775;
var Coe = eval(Coe);
var Coe = Coe * 100;
var Coe = eval(Coe);
var Coe = Math.round(Coe)/100;
var Cof = F * 1.058;
var Cof = eval(Cof);
var Cof = Cof * 100;
var Cof = eval(Cof);
var Cof = Math.round(Cof)/100;
function MM_goToURL() { //v3.0
var i, args=MM_goToURL.arguments; document.MM_returnValue = false;
for (i=0; i<(args.length-1); i+=2) eval(args[i]+".location='"+args[i+1]+"'");
}
//-->
</script>
</head>
<body bgcolor="#000066" text="#CCCCCC" link="#99FFFF" oncontextmenu="return false">
<div id="Layer3" style="position:absolute; width:200px; height:115px; z-index:4; left: 18px; top: 286px"><img src="img0.gif" width="468" height="114"></div>
<script>
document.write("The airflow is "+ F + " c.f.m. at 25 inches H2O.");
document.write("<BR>The airflow is "+ Cot + " c.f.m. at 10 inches H2O.");
document.write("<BR>The airflow is "+ Coe +" c.f.m. at 15 inches H2O.");
document.write("<BR>The airflow is "+ Cof + " c.f.m. at 28 inches H2O.");
document.write("<BR>The coefficient of discharge is " + Cd );
</script>
<div id="Layer1" style="position:absolute; width:200px; height:45px; z-index:3; left: 13px; top: 176px">
<form name="form1" >
<input type="button" name="Button2" value="Click here to evaluate more flow figures" onClick="MM_goToURL('parent','flowmaths.html');return document.MM_returnValue">
</form>
</div>
<div id="Layer4" style="position:absolute; width:475px; height:35px; z-index:5; left: 23px; top: 411px">
</div>
</body>
</html>
By floating depression I mean the bench is not set to a specific pressure drop such as 10/15/20/25/28" water. The air is pulled through an orifice in a drum with more than 4d (diameter orifice) upstream/downstream and above/below the orifice. This 'isolates' the orifice from effects of expansion and contraction of air and more or less means the efficiency is 0.596, pressure drop is measured by means of corner tappings. The test piece is upstream of the orifice with a pressure tapping to measure the drop across the piece. The flow can be calculated from the pds, temp/pressure and humidity, the maths converts the pd to whatever we decide. As I said, it has worked well since I built it in 1984.
I used the following sources to develop my bench (which took me from 1982 to 1985 to achieve repeatable results, any Unis out there who would like to give me an Honourary Degree for stubborness/persistance?).
Eastop and McConkey Applied Thermodynamics for Engineering Technologists (I actually wrote to Eastop and asked for advice only to be told it was beyond my abilities and get it done at a College....red rag to a bull!)
Ower and Pankhurst, Air Flow Measurement
Campbell The sports car engine: its tuning and modification
Annand and Roe Gas Flow in the Internal Combustion Engine
BS1042
Various publications my Chartered Surveyor Dad had on conduit flow for heating/airconditioning/ventilation
My PTS DMs have arrived so we will get to work and test em out and run em in tandem with my U manometers. Will keep folk informed.
Peter
I used the following sources to develop my bench (which took me from 1982 to 1985 to achieve repeatable results, any Unis out there who would like to give me an Honourary Degree for stubborness/persistance?).
Eastop and McConkey Applied Thermodynamics for Engineering Technologists (I actually wrote to Eastop and asked for advice only to be told it was beyond my abilities and get it done at a College....red rag to a bull!)
Ower and Pankhurst, Air Flow Measurement
Campbell The sports car engine: its tuning and modification
Annand and Roe Gas Flow in the Internal Combustion Engine
BS1042
Various publications my Chartered Surveyor Dad had on conduit flow for heating/airconditioning/ventilation
My PTS DMs have arrived so we will get to work and test em out and run em in tandem with my U manometers. Will keep folk informed.
Peter
PeterBurgess said:
Eastop and McConkey Applied Thermodynamics for Engineering Technologists (I actually wrote to Eastop and asked for advice only to be told it was beyond my abilities and get it done at a College....red rag to a bull!)
Peter
Strewth mate - if there's a few words that sums up the approach of academics to the outside world - its those. What an attitude...Peter
PeterBurgess said:
By floating depression I mean the bench is not set to a specific pressure drop such as 10/15/20/25/28" water. The air is pulled through an orifice in a drum with more than 4d (diameter orifice) upstream/downstream and above/below the orifice. This 'isolates' the orifice from effects of expansion and contraction of air and more or less means the efficiency is 0.596, pressure drop is measured by means of corner tappings. The test piece is upstream of the orifice with a pressure tapping to measure the drop across the piece. The flow can be calculated from the pds, temp/pressure and humidity, the maths converts the pd to whatever we decide. As I said, it has worked well since I built it in 1984.
I used the following sources to develop my bench (which took me from 1982 to 1985 to achieve repeatable results, any Unis out there who would like to give me an Honourary Degree for stubborness/persistance?).
Eastop and McConkey Applied Thermodynamics for Engineering Technologists (I actually wrote to Eastop and asked for advice only to be told it was beyond my abilities and get it done at a College....red rag to a bull!)
Ower and Pankhurst, Air Flow Measurement
Campbell The sports car engine: its tuning and modification
Annand and Roe Gas Flow in the Internal Combustion Engine
BS1042
Various publications my Chartered Surveyor Dad had on conduit flow for heating/airconditioning/ventilation
My PTS DMs have arrived so we will get to work and test em out and run em in tandem with my U manometers. Will keep folk informed.
Peter
Well I for one am very grateful for the work you put in Peter, and then generously shared over the years in help and assistance. Back when I was doing my A-levels too many moons ago, I had a fascination with airflow from playing with 2-stroke engines in karting (mostly messing them up than improving them, laugh) and thought I would have a go at carb design for my physics project… having read some of Peter’s (and John Robinson) articles in Performance Bikes, Performance Tuning etc these fuelled my thirst for direct practical knowledge.. I could read much in texts, but turning that into real experience and know-how was what I was lacking, and something I must say cannot be substitute as I have found in later years – real experience is invaluable. So I decided to write to Peter to tap him up on how to build a flow rig for my carb experiment project, letter below was his reply and the start of my real conversion into the dark side!I used the following sources to develop my bench (which took me from 1982 to 1985 to achieve repeatable results, any Unis out there who would like to give me an Honourary Degree for stubborness/persistance?).
Eastop and McConkey Applied Thermodynamics for Engineering Technologists (I actually wrote to Eastop and asked for advice only to be told it was beyond my abilities and get it done at a College....red rag to a bull!)
Ower and Pankhurst, Air Flow Measurement
Campbell The sports car engine: its tuning and modification
Annand and Roe Gas Flow in the Internal Combustion Engine
BS1042
Various publications my Chartered Surveyor Dad had on conduit flow for heating/airconditioning/ventilation
My PTS DMs have arrived so we will get to work and test em out and run em in tandem with my U manometers. Will keep folk informed.
Peter
PeterBurgess said:
By floating depression I mean the bench is not set to a specific pressure drop such as 10/15/20/25/28" water. The air is pulled through an orifice in a drum with more than 4d (diameter orifice) upstream/downstream and above/below the orifice. This 'isolates' the orifice from effects of expansion and contraction of air and more or less means the efficiency is 0.596, pressure drop is measured by means of corner tappings. The test piece is upstream of the orifice with a pressure tapping to measure the drop across the piece. The flow can be calculated from the pds, temp/pressure and humidity, the maths converts the pd to whatever we decide. As I said, it has worked well since I built it in 1984.
BTW- are you going to be doing a new head book at any stage, expanded math and applications for a floating depression bench? Sorry Peter - Getto Bensh :-) Having seen the re-sale price of the first editions, if you hurry up and write a new one, I can sell my old one and make some profit!! :-)Whilst on this topic, do you know what, or rather how Larry Widmer tests flow quality as a figure, in addition to flow quantity? I guess it's a laminar flow assessment, but I can only see this being upstream of the test piece?
I think you are right Martin, seeing as we are dealing with turbulent or fully developed flow at the speeds we test and the speeds in the actual running unit I cannot see how one defines quality, unless you mean flow breaking off alarmingly, in which case it sounds awful on the bench.
Peter.
Peter.
PeterBurgess said:
Hiya
I wrote an html based javascript to do the maths for my floating depression flow bench I attach the code here, to use it you need to adjust variable C if you do not agree with the 0.596 CD I use. If you copy and paste it in a text editor such as Notepad and save it as a .html or .htm extension it should fire up in a web browser, sometimes you have to tell the browser to run scripts. The script is not well written but I am self taught and it does work. It takes into account temp/pressure/humidity and assumes isentropic flow conditions. I am not going to enter into the ins and outs of the maths, suffice it to say it has been used by at least three students as part of their theses to gain Engineering degrees. If you use the code elsewhere please be polite enough to say it is written by Peter Burgess'. I hope you get as much enjoyment from flow benching as I have for the last 28 years!
Peter
Since it wants to be recursive (call itself) it really needs to be names flowmaths.htmlI wrote an html based javascript to do the maths for my floating depression flow bench I attach the code here, to use it you need to adjust variable C if you do not agree with the 0.596 CD I use. If you copy and paste it in a text editor such as Notepad and save it as a .html or .htm extension it should fire up in a web browser, sometimes you have to tell the browser to run scripts. The script is not well written but I am self taught and it does work. It takes into account temp/pressure/humidity and assumes isentropic flow conditions. I am not going to enter into the ins and outs of the maths, suffice it to say it has been used by at least three students as part of their theses to gain Engineering degrees. If you use the code elsewhere please be polite enough to say it is written by Peter Burgess'. I hope you get as much enjoyment from flow benching as I have for the last 28 years!
Peter
Stan
PS I have not really had a chance to check it out, but thanks for posting the code.
MFaulks said:
BTW- are you going to be doing a new head book at any stage, expanded math and applications for a floating depression bench? Sorry Peter - Getto Bensh :-) Having seen the re-sale price of the first editions, if you hurry up and write a new one, I can sell my old one and make some profit!! :-)
Whilst on this topic, do you know what, or rather how Larry Widmer tests flow quality as a figure, in addition to flow quantity? I guess it's a laminar flow assessment, but I can only see this being upstream of the test piece?
Hi Martin,Whilst on this topic, do you know what, or rather how Larry Widmer tests flow quality as a figure, in addition to flow quantity? I guess it's a laminar flow assessment, but I can only see this being upstream of the test piece?
How are things going?
Stan
I realise I should have defined the source of the manometer readings for the code;
X is the orifice plate pressure drop in mm of water
Y is the test piece pressure drop in mm water
I should also have stated the maths converts flow rates to STP or 1013.25 mb pressure and 15dgrees Centigrade.
Peter
X is the orifice plate pressure drop in mm of water
Y is the test piece pressure drop in mm water
I should also have stated the maths converts flow rates to STP or 1013.25 mb pressure and 15dgrees Centigrade.
Peter
PeterBurgess said:
I realise I should have defined the source of the manometer readings for the code;
X is the orifice plate pressure drop in mm of water
Y is the test piece pressure drop in mm water
I should also have stated the maths converts flow rates to STP or 1013.25 mb pressure and 15dgrees Centigrade.
Peter
Peter,X is the orifice plate pressure drop in mm of water
Y is the test piece pressure drop in mm water
I should also have stated the maths converts flow rates to STP or 1013.25 mb pressure and 15dgrees Centigrade.
Peter
Thanks for the additional information. I put together an interface to make it easier to use. I wanted to add a few more things to it but I just have not had the time. http://www.magneticlynx.com/carfor/flowmath.htm
Stan
Folks,
Just stumbled across this thread and see there's some excellent knowledge on this subject.
I'm no IT guru for writing program's etc but am a flow measurement engineer for a certain large oil company.
I'd be happy to help etc if I can on anything flow related. I was providing some data to a guy from here a couple months back on flow benches.
Thanks
Just stumbled across this thread and see there's some excellent knowledge on this subject.
I'm no IT guru for writing program's etc but am a flow measurement engineer for a certain large oil company.
I'd be happy to help etc if I can on anything flow related. I was providing some data to a guy from here a couple months back on flow benches.
Thanks
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