{"id":3258,"date":"2016-03-22T21:17:18","date_gmt":"2016-03-22T21:17:18","guid":{"rendered":"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/?p=3258"},"modified":"2016-03-22T21:17:18","modified_gmt":"2016-03-22T21:17:18","slug":"summary-of-forced-convection","status":"publish","type":"post","link":"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/summary-of-forced-convection\/","title":{"rendered":"SUMMARY OF FORCED CONVECTION"},"content":{"rendered":"<div class=\"jibnp6a0dae02c5e3a\" ><script type=\"text\/javascript\">\n\tatOptions = {\n\t\t'key' : '61e5902552e2353963d8d2f1bd1f4a8f',\n\t\t'format' : 'iframe',\n\t\t'height' : 250,\n\t\t'width' : 300,\n\t\t'params' : {}\n\t};\n<\/script>\n<script type=\"text\/javascript\" src=\"\/\/www.highperformanceformat.com\/61e5902552e2353963d8d2f1bd1f4a8f\/invoke.js\"><\/script><\/div><style type=\"text\/css\">\r\n@media screen and (min-width: 1201px) {\r\n.jibnp6a0dae02c5e3a {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 993px) and (max-width: 1200px) {\r\n.jibnp6a0dae02c5e3a {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 769px) and (max-width: 992px) {\r\n.jibnp6a0dae02c5e3a {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 768px) and (max-width: 768px) {\r\n.jibnp6a0dae02c5e3a {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (max-width: 767px) {\r\n.jibnp6a0dae02c5e3a {\r\ndisplay: block;\r\n}\r\n}\r\n<\/style>\r\n<p align=\"justify\"><font size=\"5\"><b>SUMMA<\/b><b>R<\/b><b>Y<\/b><\/font>  <\/p>\n<p align=\"justify\"><font size=\"5\">Convection is the mode of heat transfer that involves conduction as well as bulk fluid motion. The rate of convection heat transfer in external flow is expressed by <i>Newton\u2019s law of cool<\/i><\/font><font size=\"5\"><i>ing <\/i>as<\/font>  <\/p>\n<p align=\"justify\"><font size=\"5\"><a href=\"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-content\/uploads\/2016\/03\/FORCED-CONVECTION-0462.jpg\"><img decoding=\"async\" loading=\"lazy\" style=\"background-image: none; border-right-width: 0px; margin: 0px auto; padding-left: 0px; padding-right: 0px; display: block; float: none; border-top-width: 0px; border-bottom-width: 0px; border-left-width: 0px; padding-top: 0px\" title=\"FORCED CONVECTION-0462\" border=\"0\" alt=\"FORCED CONVECTION-0462\" src=\"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-content\/uploads\/2016\/03\/FORCED-CONVECTION-0462_thumb.jpg\" width=\"105\" height=\"25\"><\/a><\/font>  <\/p>\n<p align=\"justify\"><font size=\"5\">where <i>T<\/i><i>s <\/i>is the surface temperature and <i>T<\/i>X! is the free-stream temperature. The heat transfer coefficient <i>h <\/i>is usually ex<font size=\"5\">pressed in the dimensionless form as the <i>Nusselt number <\/i>as <font size=\"5\">Nu = <i>hL<\/i><i>c <\/i>\/<i>k <\/i>where <i>L<\/i><i>c <\/i>is the <i>characteristic length. <\/i>The characteristic length for noncircular tubes is the <i>hydraulic diameter <font size=\"5\"><i>D<\/i><i>h <\/i><i>defined as D<\/i><i>h <\/i>= 4<i>A<\/i><i>c <\/i>\/<i>p <\/i>where <i>A<\/i><i>c <\/i>is the cross-sectional area <font size=\"5\">of the tube and <i>p <\/i>is its perimeter. The value of the critical <\/font><font size=\"5\">Reynolds number is about 5 X 105 for flow over a flat plate, 2 X 105 for flow over cylinders and spheres, and 2300 for flow inside tubes.<\/font><\/font><\/i><\/font><\/font><\/font>  <\/p>\n<p align=\"justify\"><font size=\"5\">The average Nusselt number relations for flow over a flat plate are:<\/font>  <\/p>\n<p align=\"justify\"><font size=\"5\"><a href=\"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-content\/uploads\/2016\/03\/FORCED-CONVECTION-0463.jpg\"><img decoding=\"async\" loading=\"lazy\" style=\"background-image: none; border-right-width: 0px; margin: 0px auto; padding-left: 0px; padding-right: 0px; display: block; float: none; border-top-width: 0px; border-bottom-width: 0px; border-left-width: 0px; padding-top: 0px\" title=\"FORCED CONVECTION-0463\" border=\"0\" alt=\"FORCED CONVECTION-0463\" src=\"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-content\/uploads\/2016\/03\/FORCED-CONVECTION-0463_thumb.jpg\" width=\"270\" height=\"105\"><\/a><a href=\"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-content\/uploads\/2016\/03\/FORCED-CONVECTION-0464.jpg\"><img decoding=\"async\" loading=\"lazy\" style=\"background-image: none; border-right-width: 0px; margin: 0px auto; padding-left: 0px; padding-right: 0px; display: block; float: none; border-top-width: 0px; border-bottom-width: 0px; border-left-width: 0px; padding-top: 0px\" title=\"FORCED CONVECTION-0464\" border=\"0\" alt=\"FORCED CONVECTION-0464\" src=\"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-content\/uploads\/2016\/03\/FORCED-CONVECTION-0464_thumb.jpg\" width=\"267\" height=\"297\"><\/a><\/font>  <\/p>\n<p align=\"justify\"><font size=\"5\"><a href=\"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-content\/uploads\/2016\/03\/FORCED-CONVECTION-0465.jpg\"><img decoding=\"async\" loading=\"lazy\" style=\"background-image: none; border-right-width: 0px; margin: 0px auto; padding-left: 0px; padding-right: 0px; display: block; float: none; border-top-width: 0px; border-bottom-width: 0px; border-left-width: 0px; padding-top: 0px\" title=\"FORCED CONVECTION-0465\" border=\"0\" alt=\"FORCED CONVECTION-0465\" src=\"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-content\/uploads\/2016\/03\/FORCED-CONVECTION-0465_thumb.jpg\" width=\"260\" height=\"118\"><\/a><\/font>  <\/p><div class=\"wvtkk6a0dae02c6051\" ><script type=\"text\/javascript\">\n\tatOptions = {\n\t\t'key' : '0c1eb4c533eaedb7b996f49a5a4983a9',\n\t\t'format' : 'iframe',\n\t\t'height' : 300,\n\t\t'width' : 160,\n\t\t'params' : {}\n\t};\n<\/script>\n<script type=\"text\/javascript\" src=\"\/\/www.highperformanceformat.com\/0c1eb4c533eaedb7b996f49a5a4983a9\/invoke.js\"><\/script><\/div><style type=\"text\/css\">\r\n@media screen and (min-width: 1201px) {\r\n.wvtkk6a0dae02c6051 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 993px) and (max-width: 1200px) {\r\n.wvtkk6a0dae02c6051 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 769px) and (max-width: 992px) {\r\n.wvtkk6a0dae02c6051 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 768px) and (max-width: 768px) {\r\n.wvtkk6a0dae02c6051 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (max-width: 767px) {\r\n.wvtkk6a0dae02c6051 {\r\ndisplay: block;\r\n}\r\n}\r\n<\/style>\r\n<div class=\"dtwdb6a0dae02c5f3f\" ><script async src=\"https:\/\/pagead2.googlesyndication.com\/pagead\/js\/adsbygoogle.js?client=ca-pub-0778475562755157\"\n     crossorigin=\"anonymous\"><\/script>\n<!-- 300x600 hydraulics-and-pneumatics -->\n<ins class=\"adsbygoogle\"\n     style=\"display:inline-block;width:300px;height:600px\"\n     data-ad-client=\"ca-pub-0778475562755157\"\n     data-ad-slot=\"3735577695\"><\/ins>\n<script>\n     (adsbygoogle = window.adsbygoogle || []).push({});\n<\/script><\/div><style type=\"text\/css\">\r\n@media screen and (min-width: 1201px) {\r\n.dtwdb6a0dae02c5f3f {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 993px) and (max-width: 1200px) {\r\n.dtwdb6a0dae02c5f3f {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 769px) and (max-width: 992px) {\r\n.dtwdb6a0dae02c5f3f {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 768px) and (max-width: 768px) {\r\n.dtwdb6a0dae02c5f3f {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (max-width: 767px) {\r\n.dtwdb6a0dae02c5f3f {\r\ndisplay: block;\r\n}\r\n}\r\n<\/style>\r\n\n<p align=\"justify\"><font size=\"5\">which is valid for 3.5 &lt; Re &lt; 80,000 and 0.7 &lt; Pr &lt; 380. The fluid properties are evaluated at the film temperature <i>T<\/i><i>f <\/i>= (<i>T<\/i>X! + <i>T<\/i><i>s<\/i>)\/2 in the case of a cylinder, and at the free- stream temperature <i>T<\/i>X! (except for m<i>s <\/i>, which is evaluated at the surface temperature <i>T<\/i><i>s<\/i>) in the case of a sphere.<\/font>  <\/p>\n<p align=\"justify\"><font size=\"5\">The Reynolds number for internal flow and the hydraulic diameter are defined as<\/font>  <\/p>\n<p align=\"justify\"><font size=\"5\"><a href=\"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-content\/uploads\/2016\/03\/FORCED-CONVECTION-0466.jpg\"><img decoding=\"async\" loading=\"lazy\" style=\"background-image: none; border-right-width: 0px; margin: 0px auto; padding-left: 0px; padding-right: 0px; display: block; float: none; border-top-width: 0px; border-bottom-width: 0px; border-left-width: 0px; padding-top: 0px\" title=\"FORCED CONVECTION-0466\" border=\"0\" alt=\"FORCED CONVECTION-0466\" src=\"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-content\/uploads\/2016\/03\/FORCED-CONVECTION-0466_thumb.jpg\" width=\"197\" height=\"43\"><\/a><\/font>  <\/p>\n<p align=\"justify\"><font size=\"5\">The flow in a tube is laminar for Re &lt; 2300, turbulent for Re &gt; 4,000, and transitional in between.<\/font>  <\/p>\n<p align=\"justify\"><font size=\"5\">The length of the region from the tube inlet to the point at <\/font><font size=\"5\">which the boundary layer merges at the centerline is the <i>hydro- dynamic entry length L<\/i><i>h<\/i><i>. <\/i>The region beyond the entrance <font size=\"5\">region in which the velocity profile is fully developed is the <i>hy<\/i><\/font><font size=\"5\"><i>drodynamically fully developed region. <\/i>The length of the region of flow over which the thermal boundary layer develops <font size=\"5\">and reaches the tube center is the <i>thermal entry length L<\/i><i>t<\/i><i>. <\/i>The region in which the flow is both hydrodynamically and ther<\/font><font size=\"5\">mally developed is the <i>fully developed flow region. <\/i>The entry <\/font><font size=\"5\">lengths are given by<\/font><\/font><\/font>  <\/p>\n<p align=\"justify\"><font size=\"5\"><a href=\"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-content\/uploads\/2016\/03\/FORCED-CONVECTION-0467.jpg\"><img decoding=\"async\" loading=\"lazy\" style=\"background-image: none; border-right-width: 0px; margin: 0px auto; padding-left: 0px; padding-right: 0px; display: block; float: none; border-top-width: 0px; border-bottom-width: 0px; border-left-width: 0px; padding-top: 0px\" title=\"FORCED CONVECTION-0467\" border=\"0\" alt=\"FORCED CONVECTION-0467\" src=\"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-content\/uploads\/2016\/03\/FORCED-CONVECTION-0467_thumb.jpg\" width=\"233\" height=\"116\"><\/a><a href=\"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-content\/uploads\/2016\/03\/FORCED-CONVECTION-0468.jpg\"><img decoding=\"async\" loading=\"lazy\" style=\"background-image: none; border-right-width: 0px; margin: 0px auto; padding-left: 0px; padding-right: 0px; display: block; float: none; border-top-width: 0px; border-bottom-width: 0px; border-left-width: 0px; padding-top: 0px\" title=\"FORCED CONVECTION-0468\" border=\"0\" alt=\"FORCED CONVECTION-0468\" src=\"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-content\/uploads\/2016\/03\/FORCED-CONVECTION-0468_thumb.jpg\" width=\"267\" height=\"484\"><\/a><\/font>  <\/p>\n<p align=\"justify\">\n<h4 align=\"justify\"><font size=\"5\"><\/font><\/h4>\n","protected":false},"excerpt":{"rendered":"<p>SUMMARY Convection is the mode of heat transfer that involves conduction as well as bulk fluid motion. The rate of convection heat transfer in external flow is expressed by Newton\u2019s law of cooling as where Ts is the surface temperature and TX! is the free-stream temperature. The heat transfer coefficient h is usually expressed in [&hellip;]<br \/><a href=\"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/summary-of-forced-convection\/\" class=\"more-link\" >Continue reading&#8230;<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[1],"tags":[],"_links":{"self":[{"href":"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-json\/wp\/v2\/posts\/3258"}],"collection":[{"href":"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-json\/wp\/v2\/comments?post=3258"}],"version-history":[{"count":1,"href":"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-json\/wp\/v2\/posts\/3258\/revisions"}],"predecessor-version":[{"id":3259,"href":"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-json\/wp\/v2\/posts\/3258\/revisions\/3259"}],"wp:attachment":[{"href":"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-json\/wp\/v2\/media?parent=3258"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-json\/wp\/v2\/categories?post=3258"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-json\/wp\/v2\/tags?post=3258"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}