{"id":51178,"date":"2020-01-24T17:16:59","date_gmt":"2020-01-24T16:16:59","guid":{"rendered":"https:\/\/www.thermal-engineering.org\/o-que-e-a-lei-de-conducao-termica-de-fourier-definicao\/"},"modified":"2020-01-24T17:18:12","modified_gmt":"2020-01-24T16:18:12","slug":"o-que-e-a-lei-de-conducao-termica-de-fourier-definicao","status":"publish","type":"post","link":"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-a-lei-de-conducao-termica-de-fourier-definicao\/","title":{"rendered":"O que \u00e9 a lei de condu\u00e7\u00e3o t\u00e9rmica de Fourier – Defini\u00e7\u00e3o"},"content":{"rendered":"
\n
A lei de condu\u00e7\u00e3o t\u00e9rmica de Fourier afirma que a taxa de tempo de transfer\u00eancia de calor atrav\u00e9s de um material \u00e9 proporcional ao gradiente negativo na temperatura e na \u00e1rea.\u00a0Engenharia T\u00e9rmica<\/div>\n<\/div>\n
<\/div>\n
\n
\n
<\/div>\n

Lei de Fourier de condu\u00e7\u00e3o t\u00e9rmica<\/h2>\n

Os<\/strong>\u00a0processos de\u00a0transfer\u00eancia de calor<\/strong>\u00a0podem ser quantificados em termos de equa\u00e7\u00f5es de taxa apropriadas.\u00a0A equa\u00e7\u00e3o da taxa neste modo de transfer\u00eancia de calor \u00e9 baseada na\u00a0lei de condu\u00e7\u00e3o t\u00e9rmica de Fourier<\/strong>\u00a0.\u00a0Esta lei estabelece que a\u00a0taxa de<\/strong>\u00a0tempo\u00a0de transfer\u00eancia de calor<\/strong>\u00a0atrav\u00e9s de um material \u00e9\u00a0proporcional ao\u00a0<\/strong>gradiente<\/strong>\u00a0negativo\u00a0na temperatura<\/strong>\u00a0e \u00e0 \u00e1rea, perpendicularmente \u00e0quele gradiente, atrav\u00e9s do qual o calor flui.\u00a0Sua forma diferencial \u00e9:<\/p>\n

\"Lei<\/a><\/p>\n<\/div>\n<\/div>\n

\n
\n
<\/div>\n

A constante de proporcionalidade obtida na rela\u00e7\u00e3o \u00e9 conhecida como\u00a0condutividade t\u00e9rmica<\/strong>\u00a0,\u00a0k<\/strong>\u00a0(ou\u00a0\u03bb<\/strong>\u00a0), do material.\u00a0Um material que transfere energia prontamente por condu\u00e7\u00e3o \u00e9 um bom condutor t\u00e9rmico e possui um alto valor de\u00a0k<\/strong>\u00a0.\u00a0A lei de Fourier<\/strong>\u00a0\u00e9 uma express\u00e3o que define a\u00a0condutividade t\u00e9rmica<\/strong>\u00a0.Como pode ser visto, para resolver a\u00a0lei de Fourier<\/strong>\u00a0, precisamos envolver a diferen\u00e7a de temperatura, a geometria e a condutividade t\u00e9rmica do objeto.\u00a0Essa lei foi formulada pela primeira vez por Joseph Fourier em 1822, que concluiu que “o fluxo de calor resultante da condu\u00e7\u00e3o t\u00e9rmica \u00e9 proporcional \u00e0 magnitude do gradiente de temperatura e oposto ao sinal”.<\/p>\n

\n
\n

Da mesma forma, como a\u00a0<\/span>lei de Fourier<\/span><\/strong>\u00a0determina o fluxo de calor atrav\u00e9s de uma laje, ela tamb\u00e9m pode ser usada para determinar a diferen\u00e7a de temperatura, quando\u00a0<\/span>q<\/span><\/strong>\u00a0\u00e9 conhecido.\u00a0Isso pode ser usado para o c\u00e1lculo da temperatura no centro do pellet de combust\u00edvel, como ser\u00e1 mostrado nas se\u00e7\u00f5es a seguir.<\/span><\/p>\n<\/div>\n<\/div>\n

\n
\n
<\/div>\n

Exemplo – Fluxo de calor atrav\u00e9s de uma janela<\/span><\/h2>\n

\"Exemplo<\/a>Perda de calor atrav\u00e9s das janelas<\/span><\/strong><\/p>\n

Uma das principais fontes de perda de calor de uma casa \u00e9 atrav\u00e9s das janelas.\u00a0Calcule a taxa de fluxo de calor atrav\u00e9s de uma janela de vidro com 1,5 mx\u00a0<\/span>\u00a0<\/strong>1,0 m de \u00e1rea e 3,0 mm de espessura, se as temperaturas nas superf\u00edcies interna e externa forem de 14,0 \u00b0 C e 13,0 \u00b0 C, respectivamente.\u00a0Calcule o fluxo de calor atrav\u00e9s desta janela.<\/span><\/p>\n

Solu\u00e7\u00e3o:<\/span><\/strong><\/p>\n

Neste ponto, conhecemos as temperaturas nas superf\u00edcies do material.\u00a0Essas temperaturas s\u00e3o dadas tamb\u00e9m pelas condi\u00e7\u00f5es dentro e fora da casa.\u00a0Nesse caso, o calor flui por condu\u00e7\u00e3o atrav\u00e9s do vidro da temperatura interna mais alta para a temperatura externa mais baixa.\u00a0Usamos a\u00a0<\/span>lei<\/span><\/strong>\u00a0de\u00a0Fourier da<\/strong>\u00a0equa\u00e7\u00e3o de condu\u00e7\u00e3o t\u00e9rmica:<\/span><\/p>\n

\"Perda<\/a><\/p>\n

Assumimos que a condutividade t\u00e9rmica de um vidro comum \u00e9 k = 0,96 W \/ mK<\/span><\/p>\n

O fluxo de calor ser\u00e1 ent\u00e3o:<\/span><\/p>\n

q = 0,96 [W \/ mK] x 1 [K] \/ 3,0 x 10\u00a0<\/span>-3<\/span><\/sup>\u00a0\u00a0[m] = 320 W \/ m\u00a0<\/span>2<\/span><\/sup><\/p>\n

A perda total de calor atrav\u00e9s desta janela ser\u00e1:<\/span><\/p>\n

q\u00a0<\/span>perda<\/span><\/sub>\u00a0\u00a0= q.\u00a0A = 320 x 1,5 x 1,0 = 480W<\/span><\/p>\n<\/div>\n<\/div>\n

\n
\n
<\/div>\n

Lei de Fourier e resist\u00eancia t\u00e9rmica<\/span><\/h2>\n

\"resist\u00eancia<\/a>A resist\u00eancia t\u00e9rmica<\/span><\/a><\/strong>\u00a0\u00a0\u00e9 o inverso da condut\u00e2ncia t\u00e9rmica.\u00a0Assim como uma resist\u00eancia el\u00e9trica est\u00e1 associada \u00e0 condu\u00e7\u00e3o de eletricidade, uma resist\u00eancia t\u00e9rmica pode estar associada \u00e0 condu\u00e7\u00e3o de calor.<\/span><\/p>\n

Considere uma parede plana de espessura L e condutividade t\u00e9rmica m\u00e9dia k.\u00a0As duas superf\u00edcies da parede s\u00e3o mantidos a temperaturas constantes de T\u00a0<\/span>1<\/span><\/sub>\u00a0\u00a0e T\u00a0<\/span>2<\/span><\/sub>\u00a0.\u00a0Para condu\u00e7\u00e3o de calor constante unidimensional atrav\u00e9s da parede, temos T (x).\u00a0Ent\u00e3o\u00a0\u00a0<\/span>a lei de Fourier<\/span><\/strong>\u00a0\u00a0de\u00a0\u00a0<\/span>condu\u00e7\u00e3o de calor<\/span><\/a>\u00a0\u00a0para a parede pode ser expressa como:<\/span><\/p>\n

\"Lei<\/a><\/p>\n

A resist\u00eancia t\u00e9rmica<\/span><\/strong>\u00a0<\/a>\u00a0\u00e9 uma propriedade de calor e uma medi\u00e7\u00e3o de uma diferen\u00e7a de temperatura pela qual um objeto ou material resiste ao fluxo de calor.\u00a0A resist\u00eancia t\u00e9rmica para condu\u00e7\u00e3o em uma parede plana \u00e9 definida como:<\/span><\/p>\n

\"resist\u00eancia<\/a><\/p>\n

 <\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n

……………………………………………………………………………………………………………………………….<\/p>\n

Este artigo \u00e9 baseado na tradu\u00e7\u00e3o autom\u00e1tica do artigo original em ingl\u00eas. Para mais informa\u00e7\u00f5es, consulte o artigo em ingl\u00eas. Voc\u00ea pode nos ajudar. Se voc\u00ea deseja corrigir a tradu\u00e7\u00e3o, envie-a para: translations@nuclear-power.com ou preencha o formul\u00e1rio de tradu\u00e7\u00e3o on-line. Agradecemos sua ajuda, atualizaremos a tradu\u00e7\u00e3o o mais r\u00e1pido poss\u00edvel. Obrigado.<\/p>\n","protected":false},"excerpt":{"rendered":"

A lei de condu\u00e7\u00e3o t\u00e9rmica de Fourier afirma que a taxa de tempo de transfer\u00eancia de calor atrav\u00e9s de um material \u00e9 proporcional ao gradiente negativo na temperatura e na \u00e1rea.\u00a0Engenharia T\u00e9rmica Lei de Fourier de condu\u00e7\u00e3o t\u00e9rmica Os\u00a0processos de\u00a0transfer\u00eancia de calor\u00a0podem ser quantificados em termos de equa\u00e7\u00f5es de taxa apropriadas.\u00a0A equa\u00e7\u00e3o da taxa neste … Ler mais<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[14],"tags":[],"yoast_head":"\nO que \u00e9 a lei de condu\u00e7\u00e3o t\u00e9rmica de Fourier - Defini\u00e7\u00e3o<\/title>\n<meta name=\"description\" content=\"A lei de condu\u00e7\u00e3o t\u00e9rmica de Fourier afirma que a taxa de tempo de transfer\u00eancia de calor atrav\u00e9s de um material \u00e9 proporcional ao gradiente negativo na temperatura e na \u00e1rea. Engenharia T\u00e9rmica\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-a-lei-de-conducao-termica-de-fourier-definicao\/\" \/>\n<meta property=\"og:locale\" content=\"pt_BR\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"O que \u00e9 a lei de condu\u00e7\u00e3o t\u00e9rmica de Fourier - Defini\u00e7\u00e3o\" \/>\n<meta property=\"og:description\" content=\"A lei de condu\u00e7\u00e3o t\u00e9rmica de Fourier afirma que a taxa de tempo de transfer\u00eancia de calor atrav\u00e9s de um material \u00e9 proporcional ao gradiente negativo na temperatura e na \u00e1rea. Engenharia T\u00e9rmica\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-a-lei-de-conducao-termica-de-fourier-definicao\/\" \/>\n<meta property=\"og:site_name\" content=\"Thermal Engineering\" \/>\n<meta property=\"article:published_time\" content=\"2020-01-24T16:16:59+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2020-01-24T16:18:12+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Fourier%E2%80%99s-law-of-Thermal-Conduction-equation.png\" \/>\n<meta name=\"twitter:card\" content=\"summary\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\">\n\t<meta name=\"twitter:data1\" content=\"Nick Connor\">\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\">\n\t<meta name=\"twitter:data2\" content=\"3 minutos\">\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebSite\",\"@id\":\"https:\/\/www.thermal-engineering.org\/fr\/#website\",\"url\":\"https:\/\/www.thermal-engineering.org\/fr\/\",\"name\":\"Thermal Engineering\",\"description\":\"\",\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":\"https:\/\/www.thermal-engineering.org\/fr\/?s={search_term_string}\",\"query-input\":\"required name=search_term_string\"}],\"inLanguage\":\"pt-BR\"},{\"@type\":\"ImageObject\",\"@id\":\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-a-lei-de-conducao-termica-de-fourier-definicao\/#primaryimage\",\"inLanguage\":\"pt-BR\",\"url\":\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Fourier%E2%80%99s-law-of-Thermal-Conduction-equation.png\"},{\"@type\":\"WebPage\",\"@id\":\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-a-lei-de-conducao-termica-de-fourier-definicao\/#webpage\",\"url\":\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-a-lei-de-conducao-termica-de-fourier-definicao\/\",\"name\":\"O que \\u00e9 a lei de condu\\u00e7\\u00e3o t\\u00e9rmica de Fourier - Defini\\u00e7\\u00e3o\",\"isPartOf\":{\"@id\":\"https:\/\/www.thermal-engineering.org\/fr\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-a-lei-de-conducao-termica-de-fourier-definicao\/#primaryimage\"},\"datePublished\":\"2020-01-24T16:16:59+00:00\",\"dateModified\":\"2020-01-24T16:18:12+00:00\",\"author\":{\"@id\":\"https:\/\/www.thermal-engineering.org\/fr\/#\/schema\/person\/e8c544db9afedaec8574d6464f9398bb\"},\"description\":\"A lei de condu\\u00e7\\u00e3o t\\u00e9rmica de Fourier afirma que a taxa de tempo de transfer\\u00eancia de calor atrav\\u00e9s de um material \\u00e9 proporcional ao gradiente negativo na temperatura e na \\u00e1rea. Engenharia T\\u00e9rmica\",\"inLanguage\":\"pt-BR\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-a-lei-de-conducao-termica-de-fourier-definicao\/\"]}]},{\"@type\":\"Person\",\"@id\":\"https:\/\/www.thermal-engineering.org\/fr\/#\/schema\/person\/e8c544db9afedaec8574d6464f9398bb\",\"name\":\"Nick Connor\",\"image\":{\"@type\":\"ImageObject\",\"@id\":\"https:\/\/www.thermal-engineering.org\/fr\/#personlogo\",\"inLanguage\":\"pt-BR\",\"url\":\"https:\/\/secure.gravatar.com\/avatar\/84c0dec310b44b65da29dc9df6925239?s=96&d=mm&r=g\",\"caption\":\"Nick Connor\"}}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","_links":{"self":[{"href":"https:\/\/www.thermal-engineering.org\/pt-br\/wp-json\/wp\/v2\/posts\/51178"}],"collection":[{"href":"https:\/\/www.thermal-engineering.org\/pt-br\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.thermal-engineering.org\/pt-br\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.thermal-engineering.org\/pt-br\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.thermal-engineering.org\/pt-br\/wp-json\/wp\/v2\/comments?post=51178"}],"version-history":[{"count":0,"href":"https:\/\/www.thermal-engineering.org\/pt-br\/wp-json\/wp\/v2\/posts\/51178\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.thermal-engineering.org\/pt-br\/wp-json\/wp\/v2\/media?parent=51178"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.thermal-engineering.org\/pt-br\/wp-json\/wp\/v2\/categories?post=51178"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.thermal-engineering.org\/pt-br\/wp-json\/wp\/v2\/tags?post=51178"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}