{"id":16677,"date":"2025-06-11T18:17:18","date_gmt":"2025-06-11T18:17:18","guid":{"rendered":"https:\/\/gaviki.com\/blog\/?p=16677"},"modified":"2025-06-11T18:17:21","modified_gmt":"2025-06-11T18:17:21","slug":"stated-that-in-the-boundary-layer-conduction-convection","status":"publish","type":"post","link":"https:\/\/gaviki.com\/blog\/stated-that-in-the-boundary-layer-conduction-convection\/","title":{"rendered":"Stated that in the boundary layer conduction-convection"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">Stated that in the boundary layer conduction-convection. Determine convective heat transfer coefficient in terms of temperature gradient applying Fourier&#8217;s law of conduction.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-vivid-cyan-blue-color\"><strong>The correct answer and explanation is:<\/strong><\/mark><\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Correct Answer:<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">To determine the <strong>convective heat transfer coefficient (h)<\/strong> in terms of the <strong>temperature gradient<\/strong> using <strong>Fourier\u2019s law of conduction<\/strong>, consider a solid surface in contact with a fluid. At the boundary layer, the energy is transferred by conduction from the wall to the fluid and then by convection into the fluid bulk.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">According to <strong>Fourier\u2019s law of conduction<\/strong>: q\u2032\u2032=\u2212k(\u2202T\u2202y)y=0q&#8221; = -k \\left( \\frac{\\partial T}{\\partial y} \\right)_{y=0}<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Where:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>q\u2032\u2032q&#8221; is the heat flux at the surface (W\/m\u00b2),<\/li>\n\n\n\n<li>kk is the thermal conductivity of the fluid (W\/m\u00b7K),<\/li>\n\n\n\n<li>(\u2202T\u2202y)y=0\\left( \\frac{\\partial T}{\\partial y} \\right)_{y=0} is the temperature gradient at the wall in the direction normal to the surface.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Also, by Newton&#8217;s <strong>law of cooling<\/strong> (convective heat transfer): q\u2032\u2032=h(Ts\u2212T\u221e)q&#8221; = h (T_s &#8211; T_\\infty)<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Where:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>hh is the convective heat transfer coefficient (W\/m\u00b2\u00b7K),<\/li>\n\n\n\n<li>TsT_s is the surface temperature,<\/li>\n\n\n\n<li>T\u221eT_\\infty is the free stream (bulk fluid) temperature.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Equating both expressions for heat flux:<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">h(Ts\u2212T\u221e)=\u2212k(\u2202T\u2202y)y=0h (T_s &#8211; T_\\infty) = -k \\left( \\frac{\\partial T}{\\partial y} \\right)_{y=0} h=\u2212kTs\u2212T\u221e(\u2202T\u2202y)y=0\\boxed{h = -\\frac{k}{T_s &#8211; T_\\infty} \\left( \\frac{\\partial T}{\\partial y} \\right)_{y=0}}<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Explanation (Approx. 300 words):<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">In heat transfer, the boundary layer is a region close to the surface of a solid where temperature gradients are significant. At this interface, heat is first transferred by <strong>conduction<\/strong> due to molecular collisions and then moves into the fluid via <strong>convection<\/strong> due to bulk fluid motion.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">To relate conduction to convection, we use Fourier\u2019s law to describe the heat flux conducted from the solid surface into the fluid. This law tells us that the heat flux is proportional to the temperature gradient at the wall and the thermal conductivity of the fluid. On the other hand, Newton\u2019s law of cooling describes the same flux from a convective perspective \u2014 as being proportional to the temperature difference between the surface and the fluid bulk, multiplied by the convective heat transfer coefficient hh.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">By equating both expressions for heat flux, we bridge conduction at the wall with convection in the fluid. The resulting formula expresses hh, the convective heat transfer coefficient, as a function of the <strong>local temperature gradient<\/strong> at the wall and the temperature difference across the boundary layer.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This relationship is fundamental in heat transfer analysis, particularly in computational simulations and boundary layer theory. It shows that hh is not a fixed property but depends on the local thermal conditions and flow characteristics, especially the <strong>steepness of the temperature gradient<\/strong> at the surface. A steeper gradient indicates a higher hh, meaning more efficient heat transfer by convection.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Stated that in the boundary layer conduction-convection. Determine convective heat transfer coefficient in terms of temperature gradient applying Fourier&#8217;s law of conduction. The correct answer and explanation is: Correct Answer: To determine the convective heat transfer coefficient (h) in terms of the temperature gradient using Fourier\u2019s law of conduction, consider a solid surface in contact [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-16677","post","type-post","status-publish","format-standard","hentry","category-quiz-questions"],"_links":{"self":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/16677","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/comments?post=16677"}],"version-history":[{"count":1,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/16677\/revisions"}],"predecessor-version":[{"id":16678,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/16677\/revisions\/16678"}],"wp:attachment":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/media?parent=16677"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/categories?post=16677"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/tags?post=16677"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}