--===============1563770606330617386==
boundary="_33ECD7CD-789F-4F3F-A4FC-10109FFC7DDB_"
--_33ECD7CD-789F-4F3F-A4FC-10109FFC7DDB_
Content-Transfer-Encoding: quoted-printable
Here=E2=80=99s a couple of questions you can ask your nephew:
1) On the high pressure side of a TR2 through early TR4 radiator sits a 4 p=
si pressure relief valve (aka radiator cap). What happens when the dynamic=
head substantially exceeds 4 psi?
2) What happens when the water pump cavitates?
3) The TR2-4 water pump uses a spring-loaded face seal to keep coolant insi=
de. What happens if the dynamic coolant pressure at the seal goes substant=
ially below the atmospheric pressure outside the seal?
(1) in particular, I believe, is the main origin for the old myth about the=
coolant moving too fast without a thermostat or restrictor plate. It real=
ly can cause overheating, just not (directly) because the coolant is moving=
too fast.
Sent from Mail for Windows 10
From: dave
Sent: Sunday, July 28, 2019 6:35 PM
Subject: [TR] water pump
In the last few weeks there was some discussion about the new vs old water =
pumps.=C2=A0 Someone postulated that the newer water pumps move water faste=
r through the radiator, which results in less cooling and a hotter engine.=
=C2=A0 I asked my nephew, a mechanical engineer who is also a car person, a=
bout this.=C2=A0 here is his reply:
I think the point of confusion is the notion that increasing flow rate is a=
bad thing. I get the basic thought of it spending less time in the radiato=
r but it's one of those things that sounds correct without having any real =
science to back it up. One of the rules of thermodynamics is that flow rate=
and heat transfer are directly proportional. If you increase flow rate and=
all other things remain constant then you will reduce temperature.
For your specific use case, you're improving the efficiency of cooling beca=
use the fluid is moving more quickly through the engine. It's better to kee=
p fluid at as low of a temperature as possible and moving it very quickly m=
eans that each molecule is exposed to the heat for less time. When it gets =
to the radiator there isn't as much heat to be removed so spending less tim=
e in the radiator becomes a moot point.
--_33ECD7CD-789F-4F3F-A4FC-10109FFC7DDB_
Content-Transfer-Encoding: quoted-printable
<html xmlns:o=3D"urn:schemas-microsoft-com:office:office" xmlns:w=3D"urn:sc=
hemas-microsoft-com:office:word" xmlns:m=3D"http://schemas.microsoft.com/of=
fice/2004/12/omml" xmlns=3D"http://www.w3.org/TR/REC-html40";><head><meta ht=
tp-equiv=3DContent-Type content=3D"text/html; charset=3Dutf-8"><meta name=
=3DGenerator content=3D"Microsoft Word 15 (filtered medium)"><style><!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri",sans-serif;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:#954F72;
text-decoration:underline;}
p.MsoListParagraph, li.MsoListParagraph, div.MsoListParagraph
{mso-style-priority:34;
margin-top:0in;
margin-right:0in;
margin-bottom:0in;
margin-left:.5in;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri",sans-serif;}
.MsoChpDefault
{mso-style-type:export-only;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
/* List Definitions */
@list l0
{mso-list-id:1452162510;
mso-list-type:hybrid;
mso-list-template-ids:2023379516 -1 67698713 67698715 67698703 67698713
67=
698715 67698703 67698713 67698715;}
@list l0:level1
{mso-level-text:"%1\)";
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-.25in;}
@list l0:level2
{mso-level-number-format:alpha-lower;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-.25in;}
@list l0:level3
{mso-level-number-format:roman-lower;
mso-level-tab-stop:none;
mso-level-number-position:right;
text-indent:-9.0pt;}
@list l0:level4
{mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-.25in;}
@list l0:level5
{mso-level-number-format:alpha-lower;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-.25in;}
@list l0:level6
{mso-level-number-format:roman-lower;
mso-level-tab-stop:none;
mso-level-number-position:right;
text-indent:-9.0pt;}
@list l0:level7
{mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-.25in;}
@list l0:level8
{mso-level-number-format:alpha-lower;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-.25in;}
@list l0:level9
{mso-level-number-format:roman-lower;
mso-level-tab-stop:none;
mso-level-number-position:right;
text-indent:-9.0pt;}
ol
{margin-bottom:0in;}
ul
{margin-bottom:0in;}
--></style></head><body lang=3DEN-US link=3Dblue vlink=3D"#954F72"><div cla=
ss=3DWordSection1><p class=3DMsoNormal>Here=E2=80=99s a couple of questions=
you can ask your nephew:</p><p class=3DMsoNormal><o:p> </o:p></p><ol =
style=3D'margin-top:0in' start=3D1 type=3D1><li class=3DMsoListParagraph st=
yle=3D'margin-left:0in;mso-list:l0 level1 lfo1'>On the high pressure side o=
f a TR2 through early TR4 radiator sits a 4 psi pressure relief valve (aka =
radiator cap).=C2=A0 What happens when the dynamic head substantially excee=
ds 4 psi?</li><li class=3DMsoListParagraph style=3D'margin-left:0in;mso-lis=
t:l0 level1 lfo1'>What happens when the water pump cavitates?</li><li class=
=3DMsoListParagraph style=3D'margin-left:0in;mso-list:l0 level1 lfo1'>The T=
R2-4 water pump uses a spring-loaded face seal to keep coolant inside.=C2=
=A0 What happens if the dynamic coolant pressure at the seal goes substanti=
ally below the atmospheric pressure outside the seal?</li></ol><p class=3DM=
soNormal><o:p> </o:p></p><p class=3DMsoNormal>(1) in particular, I bel=
ieve, is the main origin for the old myth about the coolant moving too fast=
without a thermostat or restrictor plate.=C2=A0 It really can cause overhe=
ating, just not (directly) because the coolant is moving too fast.</p><p cl=
ass=3DMsoNormal><o:p> </o:p></p><p class=3DMsoNormal>Sent from <a href=
=3D"https://go.microsoft.com/fwlink/?LinkId=3D550986";>Mail</a> for Windows =
10</p><p class=3DMsoNormal><o:p> </o:p></p><div style=3D'mso-element:p=
ara-border-div;border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in=
0in 0in'><p class=3DMsoNormal style=3D'border:none;padding:0in'><b>From: <=
/b><a href=3D"mailto:dave@ranteer.com";>dave</a><br><b>Sent: </b>Sunday, Jul=
y 28, 2019 6:35 PM<br><b>Subject: </b>[TR] water pump</p></div><p class=3DM=
soNormal><o:p> </o:p></p><p class=3DMsoNormal>In the last few weeks th=
ere was some discussion about the new vs old water pumps. Someone pos=
tulated that the newer water pumps move water faster through the radiator, =
which results in less cooling and a hotter engine. I asked my nephew,=
a mechanical engineer who is also a car person, about this. here is =
his reply:<o:p></o:p></p><p class=3DMsoNormal><o:p> </o:p></p><p class=
=3DMsoNormal>I think the point of confusion is the notion that increasing f=
low rate is a bad thing. I get the basic thought of it spending less time i=
n the radiator but it's one of those things that sounds correct without hav=
ing any real science to back it up. One of the rules of thermodynamics is t=
hat flow rate and heat transfer are directly proportional. If you increase =
flow rate and all other things remain constant then you will reduce tempera=
ture.<o:p></o:p></p><p class=3DMsoNormal><o:p> </o:p></p><p class=3DMs=
oNormal>For your specific use case, you're improving the efficiency of cool=
ing because the fluid is moving more quickly through the engine. It's bette=
r to keep fluid at as low of a temperature as possible and moving it very q=
uickly means that each molecule is exposed to the heat for less time. When =
it gets to the radiator there isn't as much heat to be removed so spending =
less time in the radiator becomes a moot point.<o:p></o:p></p><p class=3DMs=
oNormal><o:p> </o:p></p></div></body></html>=
--_33ECD7CD-789F-4F3F-A4FC-10109FFC7DDB_--
--===============1563770606330617386==
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
** triumphs@autox.team.net **
Archive: http://www.team.net/pipermail/triumphs http://www.team.net/archive
--===============1563770606330617386==--
|