{"id":2171,"date":"2026-10-15T00:35:29","date_gmt":"2026-10-14T23:35:29","guid":{"rendered":"https:\/\/wpcalc.com\/pt\/engenharia\/perda-de-pressao-em-tubulacao\/"},"modified":"2026-10-15T00:35:29","modified_gmt":"2026-10-14T23:35:29","slug":"perda-de-pressao-em-tubulacao","status":"publish","type":"post","link":"https:\/\/wpcalc.com\/pt\/engenharia\/perda-de-pressao-em-tubulacao\/","title":{"rendered":"Perda de press\u00e3o em tubula\u00e7\u00e3o"},"content":{"rendered":"<section class=\"not-prose calculator-box\" aria-labelledby=\"calculator-title\"><div class=\"flex items-baseline sm:items-center justify-between gap-2 sm:gap-3\"><div class=\"flex flex-col sm:flex-row sm:items-center gap-2\"><span class=\"icon icon-calculator text-primary-700! text-base! dark:text-primary-300!\" aria-hidden=\"true\"><\/span><h2 id=\"calculator-title\" class=\"text-lg font-display font-bold\">Perda de press\u00e3o por atrito (Darcy\u2013Weisbach)<\/h2><\/div><div class=\"calcdash-favorite group\">\n  <button type=\"button\" class=\"favorite\" id=\"favorite\" data-favorite-id=\"2171\" data-favorite-title=\"Perda de press\u00e3o em tubula\u00e7\u00e3o\" data-favorite-url=\"https:\/\/wpcalc.com\/pt\/engenharia\/perda-de-pressao-em-tubulacao\/\" data-favorite-excerpt=\"Calcule a perda de press\u00e3o e a perda de carga em uma tubula\u00e7\u00e3o com a equa\u00e7\u00e3o de Darcy\u2013Weisbach e o fator de atrito de Swamee\u2013Jain. Informe o comprimento, o di\u00e2metro, a vaz\u00e3o, as propriedades do fluido e a rugosidade para obter \u0394p em kPa e psi, al\u00e9m da velocidade, do n\u00famero de Reynolds e do fator de atrito.\" aria-label=\"Adicionar aos favoritos\" data-favorite-icon=\"icon icon-pipeline\">\n    <span class=\"icon icon-shape-star-empty\" aria-hidden=\"true\"><\/span>\n  <\/button>\n  <div class=\"calcdash-favorite__tip\" aria-hidden=\"true\">\n   <span class=\"favorite-tooltip\" id=\"favorite-tooltip\"><\/span>\n  <\/div>\n  <span class=\"sr-only\" role=\"status\" id=\"favorite-status\"><\/span>\n<\/div><\/div><form action=\"https:\/\/wpcalc.com\/pt\/engenharia\/perda-de-pressao-em-tubulacao\/\" method=\"POST\" class=\"calculator\" id=\"calculator-2171\" data-post=\"2171\"><fieldset class=\"fieldset-input is-2\"><legend class=\"sr-only\">Campos de entrada<\/legend><div class=\"field has-term\" id=\"input-1\"><label for=\"field-1\">Comprimento do tubo (L)<\/label><div class=\"term\">L<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><div class=\"field-group\"><input type=\"text\" name=\"comprimento_do_tubo_l\" id=\"field-1\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" min=\"0\" value=\"100\"\/><div class=\"grid grid-cols-1\"><select id=\"field-2\" name=\"unidade\" aria-label=\"Unidade\"><option value=\"m\" selected>m<\/option><option value=\"ft\">ft<\/option><\/select><svg class=\"pointer-events-none col-start-1 row-start-1 mr-2 size-5 self-center justify-self-end text-gray-500 sm:size-4\" viewBox=\"0 0 16 16\" fill=\"currentColor\" aria-hidden=\"true\" data-slot=\"icon\">\n              <path fill-rule=\"evenodd\" d=\"M4.22 6.22a.75.75 0 0 1 1.06 0L8 8.94l2.72-2.72a.75.75 0 1 1 1.06 1.06l-3.25 3.25a.75.75 0 0 1-1.06 0L4.22 7.28a.75.75 0 0 1 0-1.06Z\" clip-rule=\"evenodd\" \/>\n            <\/svg><\/div><\/div><\/div><div class=\"field has-term\" id=\"input-2\"><label for=\"field-3\">Di\u00e2metro interno (D)<\/label><div class=\"term\">D<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><div class=\"field-group\"><input type=\"text\" name=\"dimetro_interno_d\" id=\"field-3\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" min=\"0\" value=\"100\"\/><div class=\"grid grid-cols-1\"><select id=\"field-4\" name=\"unidade\" aria-label=\"Unidade\"><option value=\"mm\" selected>mm<\/option><option value=\"in\">in<\/option><\/select><svg class=\"pointer-events-none col-start-1 row-start-1 mr-2 size-5 self-center justify-self-end text-gray-500 sm:size-4\" viewBox=\"0 0 16 16\" fill=\"currentColor\" aria-hidden=\"true\" data-slot=\"icon\">\n              <path fill-rule=\"evenodd\" d=\"M4.22 6.22a.75.75 0 0 1 1.06 0L8 8.94l2.72-2.72a.75.75 0 1 1 1.06 1.06l-3.25 3.25a.75.75 0 0 1-1.06 0L4.22 7.28a.75.75 0 0 1 0-1.06Z\" clip-rule=\"evenodd\" \/>\n            <\/svg><\/div><\/div><\/div><div class=\"field has-term\" id=\"input-3\"><label for=\"field-5\">Vaz\u00e3o (Q)<\/label><div class=\"term\">Q<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><div class=\"field-group\"><input type=\"text\" name=\"vazo_q\" id=\"field-5\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" min=\"0\" value=\"10\"\/><div class=\"grid grid-cols-1\"><select id=\"field-6\" name=\"unidade\" aria-label=\"Unidade\"><option value=\"ls\" selected>L\/s<\/option><option value=\"gpm\">US gpm<\/option><\/select><svg class=\"pointer-events-none col-start-1 row-start-1 mr-2 size-5 self-center justify-self-end text-gray-500 sm:size-4\" viewBox=\"0 0 16 16\" fill=\"currentColor\" aria-hidden=\"true\" data-slot=\"icon\">\n              <path fill-rule=\"evenodd\" d=\"M4.22 6.22a.75.75 0 0 1 1.06 0L8 8.94l2.72-2.72a.75.75 0 1 1 1.06 1.06l-3.25 3.25a.75.75 0 0 1-1.06 0L4.22 7.28a.75.75 0 0 1 0-1.06Z\" clip-rule=\"evenodd\" \/>\n            <\/svg><\/div><\/div><\/div><div class=\"field has-term\" id=\"input-4\"><label for=\"field-7\">Massa espec\u00edfica do fluido (\u03c1)<\/label><div class=\"term\">\u03c1<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><div class=\"field-group\"><input type=\"text\" name=\"massa_especfica_do_fluido_\" id=\"field-7\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" min=\"0\" value=\"998\"\/><div class=\"grid grid-cols-1\"><select id=\"field-8\" name=\"unidade\" aria-label=\"Unidade\"><option value=\"kg\" selected>kg\/m\u00b3<\/option><option value=\"lb\">lb\/ft\u00b3<\/option><\/select><svg class=\"pointer-events-none col-start-1 row-start-1 mr-2 size-5 self-center justify-self-end text-gray-500 sm:size-4\" viewBox=\"0 0 16 16\" fill=\"currentColor\" aria-hidden=\"true\" data-slot=\"icon\">\n              <path fill-rule=\"evenodd\" d=\"M4.22 6.22a.75.75 0 0 1 1.06 0L8 8.94l2.72-2.72a.75.75 0 1 1 1.06 1.06l-3.25 3.25a.75.75 0 0 1-1.06 0L4.22 7.28a.75.75 0 0 1 0-1.06Z\" clip-rule=\"evenodd\" \/>\n            <\/svg><\/div><\/div><\/div><div class=\"field has-term\" id=\"input-5\"><label for=\"field-9\">Viscosidade din\u00e2mica (\u03bc)<\/label><div class=\"term\">\u03bc<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><input type=\"text\" name=\"viscosidade_dinmica_\" id=\"field-9\" aria-describedby=\"calc-unit-9 calc-info-9\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" min=\"0\" value=\"1.002\"\/><div class=\"unit\" id=\"calc-unit-9\">mPa\u00b7s<\/div><small id=\"calc-info-9\">\u00c1gua a 20 \u00b0C \u2248 1,0 mPa\u00b7s<\/small><\/div><div class=\"field has-term\" id=\"input-6\"><label for=\"field-10\">Rugosidade do tubo (\u03b5)<\/label><div class=\"term\">\u03b5<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><div class=\"field-group\"><input type=\"text\" name=\"rugosidade_do_tubo_\" id=\"field-10\" aria-describedby=\"calc-info-10\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" min=\"0\" value=\"0.045\"\/><div class=\"grid grid-cols-1\"><select id=\"field-11\" name=\"unidade\" aria-label=\"Unidade\"><option value=\"mm\" selected>mm<\/option><option value=\"in\">in<\/option><\/select><svg class=\"pointer-events-none col-start-1 row-start-1 mr-2 size-5 self-center justify-self-end text-gray-500 sm:size-4\" viewBox=\"0 0 16 16\" fill=\"currentColor\" aria-hidden=\"true\" data-slot=\"icon\">\n              <path fill-rule=\"evenodd\" d=\"M4.22 6.22a.75.75 0 0 1 1.06 0L8 8.94l2.72-2.72a.75.75 0 1 1 1.06 1.06l-3.25 3.25a.75.75 0 0 1-1.06 0L4.22 7.28a.75.75 0 0 1 0-1.06Z\" clip-rule=\"evenodd\" \/>\n            <\/svg><\/div><\/div><small id=\"calc-info-10\">A\u00e7o comercial \u2248 0,045 mm; tubo estirado \u2248 0,0015 mm; concreto \u2248 0,3\u20133 mm<\/small><\/div><\/fieldset><div class=\"buttons\"><button type=\"submit\" data-text=\"Recalcular\" id=\"calculate-button\" data-post=\"2171\">Calcular<\/button><button type=\"reset\">Redefinir<\/button><\/div><div class=\"field is-checkbox hidden!\" id=\"field-auto-calc\"><input type=\"checkbox\" id=\"auto-calc\"><label for=\"auto-calc\">Calcular automaticamente<\/label><small>Se ativado, o resultado \u00e9 atualizado automaticamente quando voc\u00ea altera qualquer valor.<\/small><\/div><div class=\"fieldset-result is-hidden\" aria-labelledby=\"result-title\" aria-live=\"polite\" role=\"region\"> <h3 class=\"result-title bg-gradient-to-r from-primary-50 to-gray-50 dark:from-primary-900 dark:to-gray-800\" id=\"result-title\"><span class=\"icon icon-s-pulse\" aria-hidden=\"true\"><\/span> Resultados da perda por atrito<\/h3><div class=\"result-box\"><div class=\"field-result\" id=\"output-1\"><span class=\"field-title\"><span>Perda de press\u00e3o por atrito<\/span><span class=\"result-term\">\u0394p<\/span><\/span><span class=\"field-value\" id=\"result-1\" data-unit=\"kPa\"><\/span><button type=\"button\" class=\"copy-result\" data-tooltip=\"Copiar resultado\" aria-label=\"Copiar resultado\"><span class=\"copy-icon icon icon-document-copy\" aria-hidden=\"true\"><\/span><\/button><\/div><div class=\"field-result\" id=\"output-2\"><span class=\"field-title\"><span>Queda de press\u00e3o<\/span><\/span><span class=\"field-value\" id=\"result-2\" data-unit=\"psi\"><\/span><button type=\"button\" class=\"copy-result\" data-tooltip=\"Copiar resultado\" aria-label=\"Copiar resultado\"><span class=\"copy-icon icon icon-document-copy\" aria-hidden=\"true\"><\/span><\/button><\/div><div class=\"field-result\" id=\"output-3\"><span class=\"field-title\"><span>Perda de carga<\/span><span class=\"result-term\">h\u2097<\/span><\/span><span class=\"field-value\" id=\"result-3\" data-unit=\"m\"><\/span><button type=\"button\" class=\"copy-result\" data-tooltip=\"Copiar resultado\" aria-label=\"Copiar resultado\"><span class=\"copy-icon icon icon-document-copy\" aria-hidden=\"true\"><\/span><\/button><\/div><div class=\"field-result\" id=\"output-4\"><span class=\"field-title\"><span>Velocidade do escoamento<\/span><span class=\"result-term\">v<\/span><\/span><span class=\"field-value\" id=\"result-4\" data-unit=\"m\/s\"><\/span><button type=\"button\" class=\"copy-result\" data-tooltip=\"Copiar resultado\" aria-label=\"Copiar resultado\"><span class=\"copy-icon icon icon-document-copy\" aria-hidden=\"true\"><\/span><\/button><\/div><div class=\"field-result\" id=\"output-5\"><span class=\"field-title\"><span>N\u00famero de Reynolds<\/span><span class=\"result-term\">Re<\/span><\/span><span class=\"field-value\" id=\"result-5\"><\/span><button type=\"button\" class=\"copy-result\" data-tooltip=\"Copiar resultado\" aria-label=\"Copiar resultado\"><span class=\"copy-icon icon icon-document-copy\" aria-hidden=\"true\"><\/span><\/button><\/div><div class=\"field-result\" id=\"output-6\"><span class=\"field-title\"><span>Fator de atrito de Darcy<\/span><span class=\"result-term\">f<\/span><\/span><span class=\"field-value\" id=\"result-6\"><\/span><button type=\"button\" class=\"copy-result\" data-tooltip=\"Copiar resultado\" aria-label=\"Copiar resultado\"><span class=\"copy-icon icon icon-document-copy\" aria-hidden=\"true\"><\/span><\/button><\/div><\/div><div class=\"result-actions\"><button type=\"button\" class=\"copy-link\"><svg viewBox=\"0 0 20 20\" fill=\"currentColor\" aria-hidden=\"true\"><path d=\"M12.232 4.232a2.5 2.5 0 0 1 3.536 3.536l-1.225 1.224a.75.75 0 0 0 1.061 1.06l1.224-1.224a4 4 0 0 0-5.656-5.656l-3 3a4 4 0 0 0 .225 5.865.75.75 0 0 0 .977-1.138 2.5 2.5 0 0 1-.142-3.667l3-3Z\"\/><path d=\"M11.603 7.963a.75.75 0 0 0-.977 1.138 2.5 2.5 0 0 1 .142 3.667l-3 3a2.5 2.5 0 0 1-3.536-3.536l1.225-1.224a.75.75 0 0 0-1.061-1.06l-1.224 1.224a4 4 0 1 0 5.656 5.656l3-3a4 4 0 0 0-.225-5.865Z\"\/><\/svg><span class=\"copy-link__text\">Copiar link para este c\u00e1lculo<\/span><\/button><span class=\"sr-only\" role=\"status\" id=\"copy-link-status\"><\/span><\/div><\/div><a href=\"#respond\" class=\"hidden transition-opacity duration-300 opacity-0 w-50 text-sm justify-center items-center gap-2 px-4 py-2 rounded bg-gray-200 text-gray-700 hover:bg-gray-300\" id=\"leave-comment\"><span class=\"icon icon-comments\" aria-hidden=\"true\"><\/span>Deixar um coment\u00e1rio<\/a><\/form><\/section><section id=\"calc-reactions\" class=\"not-prose hidden my-12 bg-gradient-to-r from-primary-50 to-gray-50 border border-indigo-100 rounded-xl px-6 py-4 shadow-sm\" data-post=\"2171\" aria-live=\"polite\" aria-labelledby=\"calc-reactions-title\"><p id=\"calc-reactions-title\" class=\"text-sm text-gray-500 text-center mb-2\">O que voc\u00ea achou deste resultado?<\/p><div role=\"group\" aria-labelledby=\"calc-reactions-title\" class=\"grid grid-cols-3 sm:flex sm:flex-row sm:justify-around gap-4 sm:items-center sm:flex-wrap\"><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"like\"><span class=\"reaction-count\" data-reaction-count=\"like\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\ud83d\ude00 <\/span><span class=\"reaction-description font-medium\">Curti <\/span><\/button><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"helpful\"><span class=\"reaction-count\" data-reaction-count=\"helpful\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\ud83d\udca1 <\/span><span class=\"reaction-description font-medium\">\u00datil <\/span><\/button><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"confused\"><span class=\"reaction-count\" data-reaction-count=\"confused\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\ud83d\ude15 <\/span><span class=\"reaction-description font-medium\">Confuso <\/span><\/button><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"disappointed\"><span class=\"reaction-count\" data-reaction-count=\"disappointed\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\ud83d\ude1e <\/span><span class=\"reaction-description font-medium\">Decepcionado <\/span><\/button><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"inaccurate\"><span class=\"reaction-count\" data-reaction-count=\"inaccurate\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\u274c <\/span><span class=\"reaction-description font-medium\">Impreciso <\/span><\/button><\/div><div id=\"reaction-message\" class=\"hidden mt-8 rounded-md border border-primary-100 bg-white\/50 backdrop-blur-sm px-4 py-2 text-sm text-center shadow-sm\"><\/div><\/section><div class=\"calcdash-ad not-prose calcdash-ad--calc_result calcdash-ad--in-article\"><ins class=\"adsbygoogle\" style=\"display:block\" data-ad-client=\"ca-pub-1721569815777345\" data-ad-slot=\"6317458308\" data-ad-layout=\"in-article\" data-ad-format=\"fluid\"><\/ins><script>(adsbygoogle = window.adsbygoogle || []).push({});<\/script><\/div>\n<style id=\"wpcoderpro-inline-1\">.formula-box {\r\n\tborder-bottom: none !important;\r\n}<\/style><section class=\"formula-box\" aria-labelledby=\"formula-title\">\r\n\t<div id=\"formula-title\" class=\"not-prose font-display mb-4\"><span class=\"icon icon-formula\" aria-hidden=\"true\"><\/span><h2>F\u00f3rmula da perda de press\u00e3o em tubula\u00e7\u00f5es<\/h2><\/div>\r\n\t<figure class=\"not-prose formula\">\r\n\t\t<figcaption class=\"formula-title\">F\u00f3rmula<\/figcaption>\r\n\t\t<div class=\"text-base text-gray-800\" id=\"formula\">\n\\[ \\Delta p = f \\cdot \\frac{L}{D} \\cdot \\frac{\\rho v^2}{2}, \\qquad v = \\frac{4Q}{\\pi D^2} \\]\n<\/div>\r\n\t<\/figure>\r\n\t<\/p>\n<p><strong>Onde:<\/strong><\/p>\n<ul>\n<li>\\(\\Delta p\\) \u2014 perda de press\u00e3o por atrito (Pa)<\/li>\n<li>\\(f\\) \u2014 fator de atrito de Darcy (adimensional)<\/li>\n<li>\\(L\\) \u2014 comprimento do tubo (m)<\/li>\n<li>\\(D\\) \u2014 di\u00e2metro interno do tubo (m)<\/li>\n<li>\\(\\rho\\) \u2014 densidade do fluido (kg\/m\u00b3)<\/li>\n<li>\\(v\\) \u2014 velocidade m\u00e9dia do escoamento (m\/s)<\/li>\n<li>\\(Q\\) \u2014 vaz\u00e3o volum\u00e9trica (m\u00b3\/s)<\/li>\n<\/ul>\n<p>O fator de atrito de Darcy depende do regime de escoamento, caracterizado pelo n\u00famero de Reynolds \\(Re = \\dfrac{\\rho v D}{\\mu}\\). No escoamento laminar (\\(Re &lt; 2300\\)), \\(f = 64\/Re\\). No escoamento turbulento, esta calculadora usa a aproxima\u00e7\u00e3o expl\u00edcita de Swamee\u2013Jain da equa\u00e7\u00e3o de Colebrook\u2013White:<\/p>\n<p>\\[ f = \\frac{0.25}{\\left[\\log_{10}\\left(\\dfrac{\\varepsilon}{3.7D} + \\dfrac{5.74}{Re^{0.9}}\\right)\\right]^2} \\]<\/p>\n<p>A perda de carga, que corresponde \u00e0 coluna equivalente de fluido, \u00e9 \\(h_l = \\dfrac{\\Delta p}{\\rho g}\\), com \\(g = 9.81\\ \\text{m\/s}^2\\).<\/p>\n<p>\r\n<\/section>\n<style id=\"wpcoderpro-inline-2\">.calculation-box {\r\n\tborder-bottom: none !important;\r\n}<\/style><section id=\"calculation\" class=\"calculation-box\" aria-labelledby=\"calculation-title\">\r\n\t<div id=\"calculation-title\" class=\"not-prose font-display\"><span class=\"icon icon-unordered-list\" aria-hidden=\"true\"><\/span><h2>Perda de press\u00e3o em tubula\u00e7\u00e3o \u2013 exemplo de c\u00e1lculo<\/h2><\/div>\r\n\r\n<\/p>\n<p><strong>Exemplo:<\/strong> \u00e1gua a 20 \u00b0C escoa por 100 m de tubo de a\u00e7o comercial com di\u00e2metro interno de 100 mm, a uma vaz\u00e3o de 10 L\/s. Considere \\(\\rho = 998\\ \\text{kg\/m}^3\\), \\(\\mu = 1.002\\ \\text{mPa\u00b7s}\\) e \\(\\varepsilon = 0.045\\ \\text{mm}\\).<\/p>\n<p>\\[ v = \\frac{4 \\times 0.01}{\\pi \\times 0.1^2} = 1.27\\ \\text{m\/s} \\]<\/p>\n<p>\\[ Re = \\frac{998 \\times 1.27 \\times 0.1}{0.001002} \\approx 126{,}800 \\quad (\\text{turbulento}) \\]<\/p>\n<p>\\[ f = \\frac{0.25}{\\left[\\log_{10}\\left(\\dfrac{0.000045}{3.7 \\times 0.1} + \\dfrac{5.74}{126{,}800^{0.9}}\\right)\\right]^2} \\approx 0.0196 \\]<\/p>\n<p>\\[ \\Delta p = 0.0196 \\times \\frac{100}{0.1} \\times \\frac{998 \\times 1.27^2}{2} \\approx 15{,}850\\ \\text{Pa} \\]<\/p>\n<p><strong>Resultado:<\/strong> perda de press\u00e3o por atrito de cerca de 15,85 kPa (2,30 psi), o que corresponde a uma perda de carga de aproximadamente 1,62 m de \u00e1gua ao longo do tubo.<\/p>\n<p>\n\r\n<\/section>\n<h2>Como usar a calculadora<\/h2>\n<ol>\n<li>Informe o <strong>Comprimento do tubo (L)<\/strong> e escolha metros ou p\u00e9s na lista de unidades.<\/li>\n<li>Informe o <strong>Di\u00e2metro interno (D)<\/strong> do tubo em mil\u00edmetros ou polegadas. Use o di\u00e2metro interno (o furo), n\u00e3o o tamanho nominal nem o di\u00e2metro externo.<\/li>\n<li>Informe a <strong>Vaz\u00e3o (Q)<\/strong> em litros por segundo ou gal\u00f5es americanos por minuto.<\/li>\n<li>Informe a <strong>Densidade do fluido (\u03c1)<\/strong> em kg\/m\u00b3 ou lb\/ft\u00b3. A \u00e1gua a 20 \u00b0C tem cerca de 998 kg\/m\u00b3.<\/li>\n<li>Informe a <strong>Viscosidade din\u00e2mica (\u03bc)<\/strong> em mPa\u00b7s. A \u00e1gua a 20 \u00b0C tem aproximadamente 1,0 mPa\u00b7s.<\/li>\n<li>Informe a <strong>Rugosidade do tubo (\u03b5)<\/strong> em mm ou polegadas \u2014 veja os valores t\u00edpicos na tabela abaixo.<\/li>\n<li>Leia os resultados: <strong>Perda de press\u00e3o por atrito<\/strong> em kPa e psi, <strong>Perda de carga<\/strong> em metros, al\u00e9m da <strong>Velocidade de escoamento<\/strong>, do <strong>N\u00famero de Reynolds<\/strong> e do <strong>Fator de atrito de Darcy<\/strong>.<\/li>\n<\/ol>\n<h2>O que \u00e9 a perda de press\u00e3o em tubula\u00e7\u00f5es?<\/h2>\n<p>Quando um fluido escoa por um tubo, o atrito entre o fluido e a parede do tubo \u2014 e entre as camadas de fluido que se movem em velocidades diferentes \u2014 transforma energia de press\u00e3o em calor. Por isso, a press\u00e3o na extremidade a jusante \u00e9 sempre menor do que na entrada. Essa perda, chamada de perda de press\u00e3o por atrito, \u00e9 o que as bombas precisam vencer para manter o fluido em movimento. A equa\u00e7\u00e3o de Darcy\u2013Weisbach \u00e9 o modelo mais usado para calcul\u00e1-la e vale tanto para escoamento laminar quanto turbulento, para qualquer fluido newtoniano e qualquer material de tubo.<\/p>\n<p>O resultado pode ser expresso de duas maneiras: como uma diferen\u00e7a de press\u00e3o \\(\\Delta p\\) (kPa ou psi) ou como perda de carga \\(h_l\\), em metros de coluna de fluido. Em sistemas de \u00e1gua, a perda de carga costuma ser mais pr\u00e1tica, pois pode ser lida diretamente como a altura extra que a bomba precisa vencer. No exemplo acima, a bomba precisa fornecer cerca de 1,62 m de carga a cada 100 m de tubo apenas para compensar o atrito.<\/p>\n<p>O n\u00famero de Reynolds indica o regime de escoamento: abaixo de cerca de 2300, o escoamento \u00e9 laminar e o fator de atrito depende apenas de \\(Re\\); acima de aproximadamente 4000, ele \u00e9 turbulento e a rugosidade \\(\\varepsilon\\) do tubo tamb\u00e9m entra em jogo. No regime turbulento, di\u00e2metros menores e velocidades maiores aumentam a perda de press\u00e3o muito rapidamente \u2014 com vaz\u00e3o fixa, \\(\\Delta p\\) varia aproximadamente com \\(v^2\\) e de forma inversa com \\(D^5\\). Dobrar o di\u00e2metro do tubo pode reduzir as perdas por atrito em mais de 90%.<\/p>\n<h2>Valores t\u00edpicos de rugosidade de tubos<\/h2>\n<table>\n<thead>\n<tr>\n<th>Material do tubo<\/th>\n<th>Rugosidade absoluta \u03b5 (mm)<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Tubos trefilados (cobre, pl\u00e1stico)<\/td>\n<td>0,0015<\/td>\n<\/tr>\n<tr>\n<td>A\u00e7o comercial<\/td>\n<td>0,045<\/td>\n<\/tr>\n<tr>\n<td>A\u00e7o galvanizado<\/td>\n<td>0,15<\/td>\n<\/tr>\n<tr>\n<td>Ferro fundido<\/td>\n<td>0,26<\/td>\n<\/tr>\n<tr>\n<td>Concreto<\/td>\n<td>0,3 \u2013 3<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2>Premissas e limita\u00e7\u00f5es<\/h2>\n<ul>\n<li>O c\u00e1lculo cobre <strong>apenas o atrito em tubo reto<\/strong>. Conex\u00f5es, v\u00e1lvulas, curvas, entradas e sa\u00eddas geram perdas localizadas, que voc\u00ea precisa estimar \u00e0 parte (geralmente como comprimentos equivalentes ou coeficientes de perda) e somar a este resultado.<\/li>\n<p>&lt;liAssume-se que o fluido \u00e9 <strong>newtoniano e incompress\u00edvel<\/strong>, que o escoamento \u00e9 permanente e que o tubo tem di\u00e2metro constante. Gases s\u00f3 podem ser aproximados quando a perda de press\u00e3o \u00e9 uma pequena fra\u00e7\u00e3o da press\u00e3o absoluta.<\/li>\n<li>A aproxima\u00e7\u00e3o de Swamee\u2013Jain \u00e9 precisa em cerca de 1% em rela\u00e7\u00e3o \u00e0 equa\u00e7\u00e3o de Colebrook\u2013White para \\(Re &gt; 4000\\); entre 2300 e 4000 (a zona de transi\u00e7\u00e3o), o fator de atrito \u00e9 inerentemente incerto; portanto, trate os resultados dessa faixa como estimativas.<\/li>\n<li>A calculadora pressup\u00f5e que o valor de rugosidade seja representativo das condi\u00e7\u00f5es do tubo. Tubos velhos, corro\u00eddos ou incrustados podem ter rugosidade muito maior do que tubos novos e limpos, e lodo ou dep\u00f3sitos ainda reduzem o di\u00e2metro na pr\u00e1tica.<\/li>\n<li>Use sempre o <strong>di\u00e2metro interno<\/strong>: os tamanhos nominais de tubo (por exemplo, \"tubo de a\u00e7o de 2 polegadas\") diferem do furo real, e a perda de press\u00e3o \u00e9 extremamente sens\u00edvel a esse valor.<\/li>\n<\/ul>\n<h2>Dicas pr\u00e1ticas<\/h2>\n<p>Antes de dimensionar uma bomba, some as perdas por atrito de todos os trechos de tubo \u00e0s perdas localizadas de todas as conex\u00f5es, e lembre-se de que a bomba tamb\u00e9m precisa vencer qualquer desn\u00edvel e fornecer a press\u00e3o residual exigida na sa\u00edda. Uma recomenda\u00e7\u00e3o usual de projeto \u00e9 manter a velocidade da \u00e1gua entre 1 e 3 m\/s: muito abaixo disso, o tubo fica superdimensionado e caro; muito acima, as perdas por atrito, o ru\u00eddo e o risco de golpe de ar\u00edete crescem rapidamente.<\/p>\n<p>Curiosamente, a perda de press\u00e3o em um tubo \u00e9 regida por equa\u00e7\u00f5es muito parecidas com as da queda de tens\u00e3o em um condutor \u2014 a press\u00e3o se comporta como a tens\u00e3o, a vaz\u00e3o como a corrente e o fator de atrito como a resist\u00eancia. Se voc\u00ea tamb\u00e9m trabalha com sistemas el\u00e9tricos, veja nossas calculadoras de <a href=\"https:\/\/wpcalc.com\/pt\/engenharia\/queda-de-tensao-eletrica\/\">Queda de tens\u00e3o<\/a> e <a href=\"https:\/\/wpcalc.com\/pt\/engenharia\/lei-de-ohm\/\">Lei de Ohm<\/a>, ou a calculadora de <a href=\"https:\/\/wpcalc.com\/pt\/engenharia\/bitola-de-fio-awg\/\">Bitola de fio<\/a> para dimensionar condutores pela capacidade de condu\u00e7\u00e3o de corrente.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Calcule a perda de press\u00e3o e a perda de carga em uma tubula\u00e7\u00e3o com a equa\u00e7\u00e3o de Darcy\u2013Weisbach e o fator de atrito de Swamee\u2013Jain. Informe o comprimento, o di\u00e2metro, a vaz\u00e3o, as propriedades do fluido e a rugosidade para obter \u0394p em kPa e psi, al\u00e9m da velocidade, do n\u00famero de Reynolds e do fator de atrito.<\/p>\n","protected":false},"author":3168,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[6],"tags":[63],"class_list":["post-2171","post","type-post","status-publish","format-standard","hentry","category-engenharia","tag-tubagem"],"acf":[],"_links":{"self":[{"href":"https:\/\/wpcalc.com\/pt\/wp-json\/wp\/v2\/posts\/2171","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wpcalc.com\/pt\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/wpcalc.com\/pt\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/wpcalc.com\/pt\/wp-json\/wp\/v2\/users\/3168"}],"replies":[{"embeddable":true,"href":"https:\/\/wpcalc.com\/pt\/wp-json\/wp\/v2\/comments?post=2171"}],"version-history":[{"count":1,"href":"https:\/\/wpcalc.com\/pt\/wp-json\/wp\/v2\/posts\/2171\/revisions"}],"predecessor-version":[{"id":2572,"href":"https:\/\/wpcalc.com\/pt\/wp-json\/wp\/v2\/posts\/2171\/revisions\/2572"}],"wp:attachment":[{"href":"https:\/\/wpcalc.com\/pt\/wp-json\/wp\/v2\/media?parent=2171"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wpcalc.com\/pt\/wp-json\/wp\/v2\/categories?post=2171"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wpcalc.com\/pt\/wp-json\/wp\/v2\/tags?post=2171"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}