{"id":49290,"date":"2019-11-16T00:47:16","date_gmt":"2019-11-15T23:47:16","guid":{"rendered":"https:\/\/www.thermal-engineering.org\/o-que-e-cabeca-de-succao-positiva-liquida-definicao\/"},"modified":"2020-02-01T09:16:40","modified_gmt":"2020-02-01T08:16:40","slug":"o-que-e-cabeca-de-succao-positiva-liquida-definicao","status":"publish","type":"post","link":"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-cabeca-de-succao-positiva-liquida-definicao\/","title":{"rendered":"O que \u00e9 cabe\u00e7a de suc\u00e7\u00e3o positiva l\u00edquida &#8211; Defini\u00e7\u00e3o"},"content":{"rendered":"<div class=\"su-quote su-quote-style-default\">\n<div class=\"su-quote-inner su-clearfix\">A cabe\u00e7a de suc\u00e7\u00e3o positiva l\u00edquida ou NPSH para bombas pode ser definida como a diferen\u00e7a entre a press\u00e3o de suc\u00e7\u00e3o e a press\u00e3o de satura\u00e7\u00e3o do fluido.\u00a0Engenharia T\u00e9rmica<\/div>\n<\/div>\n<div class=\"su-divider su-divider-style-dotted\"><\/div>\n<div class=\"lgc-column lgc-grid-parent lgc-grid-100 lgc-tablet-grid-100 lgc-mobile-grid-100 lgc-equal-heights lgc-first lgc-last\">\n<div class=\"inside-grid-column\">\n<div class=\"su-spacer\"><\/div>\n<h2>Cabe\u00e7a de suc\u00e7\u00e3o positiva l\u00edquida<\/h2>\n<p><strong><br \/>\n<a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Net-Positive-Suction-Head-chart.png\"><img loading=\"lazy\" class=\"alignright wp-image-15002 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Net-Positive-Suction-Head-chart.png\" alt=\"Cabe\u00e7a de suc\u00e7\u00e3o positiva l\u00edquida\" width=\"435\" height=\"237\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Net-Positive-Suction-Head-chart.png\" \/><\/a>A cabe\u00e7a de suc\u00e7\u00e3o positiva l\u00edquida<\/strong>\u00a0ou\u00a0<strong>NPSH<\/strong>\u00a0para bombas pode ser definida como a\u00a0<strong>diferen\u00e7a<\/strong>\u00a0entre a\u00a0<strong>press\u00e3o de suc\u00e7\u00e3o<\/strong>\u00a0e a\u00a0<strong>press\u00e3o<\/strong>\u00a0de\u00a0<strong>satura\u00e7\u00e3o<\/strong>\u00a0do fluido, expressa em termos de altura da coluna de l\u00edquido.\u00a0O NPSH \u00e9 usado para medir\u00a0<strong>a proximidade de<\/strong>\u00a0um fluido a condi\u00e7\u00f5es saturadas.\u00a0Baixar a press\u00e3o no lado da suc\u00e7\u00e3o pode induzir\u00a0<a title=\"Cavita\u00e7\u00e3o em Bombas Centr\u00edfugas\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/fluid-dynamics\/centrifugal-pumps\/cavitation\/\"><strong>cavita\u00e7\u00e3o<\/strong><\/a>.\u00a0Se ocorrer cavita\u00e7\u00e3o, o violento colapso da bolha de cavita\u00e7\u00e3o cria uma onda de choque que pode esculpir o material dos componentes internos da bomba (geralmente a borda principal do impulsor) e cria um ru\u00eddo geralmente descrito como \u201ccascalho de bombeamento\u201d.\u00a0Al\u00e9m disso, o inevit\u00e1vel aumento da vibra\u00e7\u00e3o pode causar outras falhas mec\u00e2nicas na bomba e nos equipamentos associados.<\/p>\n<p><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Net-Positive-Suction-Head-definition.png\"><img loading=\"lazy\" class=\"aligncenter size-full wp-image-15003 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Net-Positive-Suction-Head-definition.png\" alt=\"Cabe\u00e7a de suc\u00e7\u00e3o positiva l\u00edquida - defini\u00e7\u00e3o\" width=\"473\" height=\"145\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Net-Positive-Suction-Head-definition.png\" \/><\/a><\/p>\n<p>Em geral, existem duas cabe\u00e7as de suc\u00e7\u00e3o definidas na hidr\u00e1ulica:<\/p>\n<ul>\n<li><strong>NPSH dispon\u00edvel (NPSHa)<\/strong>\u00a0: a press\u00e3o absoluta na porta de suc\u00e7\u00e3o da bomba.\u00a0NPSHa \u00e9 uma fun\u00e7\u00e3o da temperatura da \u00e1gua.\u00a0\u00c0 medida que a temperatura de entrada aumenta, o NPSHa diminui, porque a press\u00e3o de satura\u00e7\u00e3o diminui.<\/li>\n<li><strong>NPSH necess\u00e1rio (NPSHR):<\/strong>\u00a0a press\u00e3o m\u00ednima exigida na porta de suc\u00e7\u00e3o da bomba para impedir que ela caia.\u00a0NPSHa n\u00e3o \u00e9 fun\u00e7\u00e3o da temperatura da \u00e1gua.<\/li>\n<\/ul>\n<p>O NPSHA \u00e9 uma fun\u00e7\u00e3o do seu sistema e deve ser calculado, enquanto o NPSHR \u00e9 uma fun\u00e7\u00e3o da bomba e deve ser fornecido pelo fabricante da bomba.\u00a0Durante a opera\u00e7\u00e3o, o NPSH dispon\u00edvel deve ser mantido em um n\u00edvel superior ao NPSH exigido pelo fabricante da bomba.\u00a0Verificou-se que as taxas de cavita\u00e7\u00e3o\u00a0<strong>aumentam rapidamente<\/strong>\u00a0com o aumento da taxa de fluxo de volume.\u00a0Isso pode ser visto na imagem, \u00e0 medida que a taxa de fluxo de volume aumenta, o NPSH necess\u00e1rio aumenta, mas o NPSH dispon\u00edvel diminui.<\/p>\n<h2>Como aumentar o NPSH dispon\u00edvel?<\/h2>\n<p><span>Para evitar a cavita\u00e7\u00e3o por suc\u00e7\u00e3o, o NPSH dispon\u00edvel deve ser aumentado o m\u00e1ximo poss\u00edvel.\u00a0A \u00fanica maneira de aumentar o NPSH dispon\u00edvel \u00e9 aumentar a press\u00e3o na entrada da bomba:<\/span><\/p>\n<ul>\n<li><span>Abaixe o n\u00edvel da bomba<\/span><\/li>\n<li><span>Aumente o n\u00edvel do reservat\u00f3rio<\/span><\/li>\n<li><span>Redu\u00e7\u00e3o da rota\u00e7\u00e3o do motor, se poss\u00edvel<\/span><\/li>\n<li><span>Reduza\u00a0<\/span><a title=\"Menor Perda de Cabe\u00e7a - Perdas Locais\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/fluid-dynamics\/minor-head-loss-local-losses\/\"><span>pequenas perdas a<\/span><\/a><span>\u00a0\u00a0montante da bomba<\/span><\/li>\n<li><span>Reduza\u00a0<\/span><a title=\"Perda de Cabe\u00e7a Maior - Perda de Fric\u00e7\u00e3o\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/fluid-dynamics\/major-head-loss-friction-loss\/\"><span>grandes perdas a<\/span><\/a><span>\u00a0\u00a0montante da bomba<\/span>\n<ul>\n<li><span>Encurte o comprimento do tubo<\/span><\/li>\n<li><span>Use um tubo mais liso<\/span><\/li>\n<\/ul>\n<\/li>\n<li><span>Aumento do di\u00e2metro do olho do impulsor<\/span><\/li>\n<li><span>Uso de uma bomba auxiliar para alimentar a bomba principal.<\/span><\/li>\n<\/ul>\n<\/div>\n<p>&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;.<\/p>\n<p>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<\/div>\n","protected":false},"excerpt":{"rendered":"<p>A cabe\u00e7a de suc\u00e7\u00e3o positiva l\u00edquida ou NPSH para bombas pode ser definida como a diferen\u00e7a entre a press\u00e3o de suc\u00e7\u00e3o e a press\u00e3o de satura\u00e7\u00e3o do fluido.\u00a0Engenharia T\u00e9rmica Cabe\u00e7a de suc\u00e7\u00e3o positiva l\u00edquida A cabe\u00e7a de suc\u00e7\u00e3o positiva l\u00edquida\u00a0ou\u00a0NPSH\u00a0para bombas pode ser definida como a\u00a0diferen\u00e7a\u00a0entre a\u00a0press\u00e3o de suc\u00e7\u00e3o\u00a0e a\u00a0press\u00e3o\u00a0de\u00a0satura\u00e7\u00e3o\u00a0do fluido, expressa em termos de &#8230; <a title=\"O que \u00e9 cabe\u00e7a de suc\u00e7\u00e3o positiva l\u00edquida &#8211; Defini\u00e7\u00e3o\" class=\"read-more\" href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-cabeca-de-succao-positiva-liquida-definicao\/\" aria-label=\"More on O que \u00e9 cabe\u00e7a de suc\u00e7\u00e3o positiva l\u00edquida &#8211; Defini\u00e7\u00e3o\">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":"<!-- This site is optimized with the Yoast SEO plugin v15.4 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>O que \u00e9 cabe\u00e7a de suc\u00e7\u00e3o positiva l\u00edquida - Defini\u00e7\u00e3o<\/title>\n<meta name=\"description\" content=\"A cabe\u00e7a de suc\u00e7\u00e3o positiva l\u00edquida ou NPSH para bombas pode ser definida como a diferen\u00e7a entre a press\u00e3o de suc\u00e7\u00e3o e a press\u00e3o de satura\u00e7\u00e3o do fluido. 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