{"id":45631,"date":"2019-10-19T21:27:04","date_gmt":"2019-10-19T20:27:04","guid":{"rendered":"https:\/\/www.thermal-engineering.org\/quest-ce-quun-exemple-denthalpie-calcul-definition\/"},"modified":"2020-02-25T17:34:30","modified_gmt":"2020-02-25T16:34:30","slug":"quest-ce-quun-exemple-denthalpie-calcul-definition","status":"publish","type":"post","link":"https:\/\/www.thermal-engineering.org\/fr\/quest-ce-quun-exemple-denthalpie-calcul-definition\/","title":{"rendered":"Exemple d&#8217;enthalpie &#8211; Calcul &#8211; D\u00e9finition"},"content":{"rendered":"<div class=\"su-quote su-quote-style-default\">\n<div class=\"su-quote-inner su-clearfix\">Exemples d&#8217;enthalpie &#8211; Calcul de l&#8217;enthalpie.\u00a0Piston sans friction, bilan \u00e9nerg\u00e9tique, enthalpie sp\u00e9cifique de la vapeur humide.\u00a0Exemples et solutions.\u00a0G\u00e9nie thermique<\/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>Enthalpie en unit\u00e9s extensives<\/h2>\n<figure id=\"attachment_16538\" class=\"wp-caption alignright\" aria-describedby=\"caption-attachment-16538\"><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Extensive-vs.-Intensive-properties-min.png\"><img loading=\"lazy\" class=\"size-medium wp-image-16538 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Extensive-vs.-Intensive-properties-min-238x300.png\" alt=\"Propri\u00e9t\u00e9s thermodynamiques extensives et intensives\" width=\"238\" height=\"300\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Extensive-vs.-Intensive-properties-min-238x300.png\" \/><\/a><figcaption id=\"caption-attachment-16538\" class=\"wp-caption-text\">Propri\u00e9t\u00e9s \u00e9tendues et intensives du milieu dans le pressuriseur.<\/figcaption><\/figure>\n<p><em><strong>H = U + pV<\/strong><\/em><\/p>\n<p><strong>L&#8217;enthalpie<\/strong>\u00a0\u00a0est une quantit\u00e9 importante, elle d\u00e9pend de la taille du syst\u00e8me ou de la quantit\u00e9 de substance qu&#8217;il contient.\u00a0L&#8217;unit\u00e9 SI d&#8217;enthalpie est le joule (J).\u00a0C&#8217;est l&#8217;\u00e9nergie contenue dans le syst\u00e8me, \u00e0 l&#8217;exclusion de l&#8217;\u00e9nergie cin\u00e9tique de mouvement du syst\u00e8me dans son ensemble et de l&#8217;\u00e9nergie potentielle du syst\u00e8me dans son ensemble en raison des champs de forces externes.\u00a0C&#8217;est la quantit\u00e9 thermodynamique \u00e9quivalente au\u00a0<strong>contenu thermique total<\/strong>\u00a0d&#8217;un syst\u00e8me.<\/p>\n<p>D&#8217;autre part, de l&#8217;\u00e9nergie peut \u00eatre stock\u00e9e dans les liaisons chimiques entre les atomes qui composent les mol\u00e9cules.\u00a0Ce stockage d&#8217;\u00e9nergie au niveau atomique inclut l&#8217;\u00e9nergie associ\u00e9e aux \u00e9tats orbitaux des \u00e9lectrons, au spin nucl\u00e9aire et aux forces de liaison dans le noyau.<\/p>\n<p><strong>L&#8217;enthalpie<\/strong>\u00a0est repr\u00e9sent\u00e9e par le symbole\u00a0<strong>H<\/strong>\u00a0et le changement d&#8217;enthalpie dans un processus est\u00a0<strong>H\u00a0<sub>2<\/sub>\u00a0&#8211; H\u00a0<sub>1<\/sub><\/strong>\u00a0.<\/p>\n<p>Il existe des expressions en termes de variables plus famili\u00e8res telles que la\u00a0<a title=\"Quelle est la temp\u00e9rature - Physique\" href=\"https:\/\/www.thermal-engineering.org\/fr\/quest-ce-que-la-temperature-physique-definition\/\">temp\u00e9rature<\/a>\u00a0et la\u00a0<a title=\"Qu'est-ce que la pression - Physique\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/thermodynamic-properties\/what-is-pressure-physics\/\">pression<\/a>\u00a0:<\/p>\n<p><em><strong>dH = C\u00a0<sub>p<\/sub>\u00a0dT + V (1-aT) dp<\/strong><\/em><\/p>\n<p>O\u00f9\u00a0<strong>C\u00a0<sub>p<\/sub><\/strong>\u00a0est la\u00a0<strong>capacit\u00e9 thermique \u00e0 pression constante<\/strong>\u00a0et\u00a0<strong><em>\u03b1<\/em><\/strong>\u00a0le coefficient de dilatation thermique (cubique).\u00a0Pour le gaz parfait, \u03b1T = 1 et donc:<\/p>\n<p><em><strong>dH = C\u00a0<sub>p<\/sub>\u00a0dT<\/strong><\/em><\/p>\n<\/div>\n<\/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<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<h2><span>Exemple: Piston sans friction &#8211; Chaleur &#8211; Enthalpie<\/span><\/h2>\n<figure id=\"attachment_16678\" class=\"wp-caption alignright\" aria-describedby=\"caption-attachment-16678\"><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Enthalpy-example-min.png\"><img loading=\"lazy\" class=\"size-medium wp-image-16678 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Enthalpy-example-min-224x300.png\" alt=\"Enthalpie - Exemple - Un piston sans friction\" width=\"224\" height=\"300\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Enthalpy-example-min-224x300.png\" \/><\/a><figcaption id=\"caption-attachment-16678\" class=\"wp-caption-text\"><span>Calculez la temp\u00e9rature finale, si 3000 kJ de chaleur sont ajout\u00e9s.<\/span><\/figcaption><\/figure>\n<p><span>Un piston sans\u00a0frottement est utilis\u00e9 pour fournir une pression constante de\u00a0<\/span><strong><span>500 kPa<\/span><\/strong><span>\u00a0en une vapeur contenant de cylindre (\u00a0<\/span><a title=\"Vapeur surchauff\u00e9e\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/materials-nuclear-engineering\/properties-steam-what-is-steam\/superheated-steam\/\"><span>vapeur surchauff\u00e9e<\/span><\/a><span>\u00a0) d&#8217;un volume de\u00a0<\/span><strong><span>2 m\u00a0<\/span><sup><span>3<\/span><\/sup><\/strong><span>\u00a0\u00a0\u00e0\u00a0<\/span><strong><span>500 K<\/span><\/strong><span>\u00a0.\u00a0Calculez la temp\u00e9rature finale, si\u00a0<\/span><strong><span>3000 kJ<\/span><\/strong><span>\u00a0de\u00a0<\/span><strong><span>chaleur<\/span><\/strong><span>\u00a0sont ajout\u00e9s.<\/span><\/p>\n<p><strong><span>Solution:<\/span><\/strong><\/p>\n<p><span>En utilisant\u00a0<\/span><a title=\"Tables \u00e0 vapeur - Propri\u00e9t\u00e9s sp\u00e9cifiques de l'eau et de la vapeur\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/steam-tables\/\"><span>des tables \u00e0 vapeur,<\/span><\/a><span>\u00a0nous savons que l&#8217;\u00a0<\/span><strong><span>enthalpie sp\u00e9cifique<\/span><\/strong><span>\u00a0de cette vapeur (500 kPa; 500 K) est d&#8217;environ\u00a0<\/span><strong><span>2912 kJ \/ kg<\/span><\/strong><span>\u00a0.\u00a0\u00c9tant donn\u00e9 qu&#8217;\u00e0 cette condition, la vapeur a une densit\u00e9 de 2,2 kg \/ m\u00a0<\/span><sup><span>3<\/span><\/sup><span>\u00a0, alors nous savons qu&#8217;il y a environ\u00a0<\/span><strong><span>4,4 kg de vapeur<\/span><\/strong><span>\u00a0dans le piston \u00e0 l&#8217;enthalpie de 2912 kJ \/ kg x 4,4 kg =\u00a0<\/span><strong><span>12812 kJ<\/span><\/strong><span>\u00a0.<\/span><\/p>\n<p><span>Lorsque nous utilisons simplement\u00a0<\/span><strong><span>Q = H\u00a0<\/span><sub><span>2<\/span><\/sub><span>\u00a0&#8211; H\u00a0<\/span><sub><span>1<\/span><\/sub><\/strong><span>\u00a0, l&#8217;enthalpie de vapeur r\u00e9sultante sera alors:<\/span><\/p>\n<p><span>H\u00a0<\/span><sub><span>2<\/span><\/sub><span>\u00a0= H\u00a0<\/span><sub><span>1<\/span><\/sub><span>\u00a0+ Q =\u00a0<\/span><strong><span>15812 kJ<\/span><\/strong><\/p>\n<p><span>A partir\u00a0<\/span><strong><span>des tables \u00e0 vapeur<\/span><\/strong><span>\u00a0, une telle vapeur surchauff\u00e9e (15812 \/ 4,4 = 3593 kJ \/ kg) aura une temp\u00e9rature de\u00a0<\/span><strong><span>828 K (555 \u00b0 C)<\/span><\/strong><span>\u00a0.\u00a0Comme \u00e0 cette enthalpie, la vapeur a une densit\u00e9 de 1,31 kg \/ m\u00a0<\/span><sup><span>3<\/span><\/sup><span>\u00a0, il est \u00e9vident qu&#8217;elle a augment\u00e9 d&#8217;environ 2,2 \/ 1,31 = 1,67 (+ 67%).\u00a0Par cons\u00e9quent, le volume r\u00e9sultant est de 2 m\u00a0<\/span><sup><span>3<\/span><\/sup><span>\u00a0x 1,67 = 3,34 m\u00a0<\/span><sup><span>3<\/span><\/sup><span>\u00a0et \u2206V = 3,34 m\u00a0<\/span><sup><span>3<\/span><\/sup><span>\u00a0&#8211; 2 m\u00a0<\/span><sup><span>3<\/span><\/sup><span>\u00a0= 1,34 m\u00a0<\/span><sup><span>3<\/span><\/sup><span>\u00a0.<\/span><\/p>\n<p><span>La\u00a0partie\u00a0<\/span><strong><span>p\u2206V<\/span><\/strong><span>\u00a0de l&#8217;enthalpie, c&#8217;est-\u00e0-dire le travail effectu\u00e9 est:<\/span><\/p>\n<p><strong><span>W = p\u2206V = 500 000 Pa x 1,34 m\u00a0<\/span><sup><span>3<\/span><\/sup><span>\u00a0= 670 kJ<\/span><\/strong><\/p>\n<\/div>\n<\/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><span>Exemple: bilan \u00e9nerg\u00e9tique d&#8217;un g\u00e9n\u00e9rateur de vapeur<\/span><\/h2>\n<figure id=\"attachment_407\" class=\"wp-caption alignright\" aria-describedby=\"caption-attachment-407\"><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/STEAM_GENERATOR_NUCLEAR.gif\"><img loading=\"lazy\" class=\"size-medium wp-image-407 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/STEAM_GENERATOR_NUCLEAR-223x300.gif\" alt=\"G\u00e9n\u00e9rateur de vapeur - vertical\" width=\"223\" height=\"300\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/STEAM_GENERATOR_NUCLEAR-223x300.gif\" \/><\/a><figcaption id=\"caption-attachment-407\" class=\"wp-caption-text\"><span>G\u00e9n\u00e9rateur de vapeur &#8211; vertical<\/span><\/figcaption><\/figure>\n<p><span>Calculez la quantit\u00e9 de liquide de refroidissement primaire, qui est n\u00e9cessaire pour\u00a0<\/span><strong><span>\u00e9vaporer 1 kg d&#8217;eau d&#8217;alimentation<\/span><\/strong><span>\u00a0dans un\u00a0<\/span><a title=\"G\u00e9n\u00e9rateur de vapeur\" href=\"https:\/\/www.nuclear-power.com\/steam-generator\/\"><span>g\u00e9n\u00e9rateur de vapeur<\/span><\/a><span>\u00a0typique\u00a0.\u00a0Supposons qu&#8217;il n&#8217;y ait pas de pertes d&#8217;\u00e9nergie, ce n&#8217;est qu&#8217;un exemple id\u00e9alis\u00e9.<\/span><\/p>\n<p><strong><span>Equilibre du circuit primaire<\/span><\/strong><\/p>\n<p><span>Le liquide de refroidissement primaire chaud (\u00a0<\/span><strong><span>eau 330 \u00b0 C; 626 \u00b0 F; 16 MPa<\/span><\/strong><span>\u00a0) est pomp\u00e9 dans\u00a0<\/span><strong><span>le g\u00e9n\u00e9rateur de vapeur<\/span><\/strong><span>\u00a0par l&#8217;entr\u00e9e primaire.\u00a0Le liquide de refroidissement primaire laisse\u00a0<\/span><strong><span>(eau 295 \u00b0 C; 563 \u00b0 F; 16 MPa)<\/span><\/strong><span>\u00a0le g\u00e9n\u00e9rateur de vapeur par la sortie primaire.<\/span><\/p>\n<p><span>h\u00a0<\/span><sub><span>I, entr\u00e9e<\/span><\/sub><span>\u00a0= 1516 kJ \/ kg<\/span><\/p>\n<p><span>=&gt; \u0394h\u00a0<\/span><sub><span>I<\/span><\/sub><span>\u00a0= -206 kJ \/ kg<\/span><\/p>\n<p><span>h\u00a0<\/span><sub><span>I, sortie<\/span><\/sub><span>\u00a0= 1310 kJ \/ kg<\/span><\/p>\n<p><strong><span>\u00c9quilibre de l&#8217;eau d&#8217;alimentation<\/span><\/strong><\/p>\n<p><span>L&#8217;eau d&#8217;alimentation (\u00a0<\/span><strong><span>eau 230 \u00b0 C; 446 \u00b0 F; 6,5 MPa<\/span><\/strong><span>\u00a0) est pomp\u00e9e dans\u00a0<\/span><strong><span>le g\u00e9n\u00e9rateur de vapeur<\/span><\/strong><span>\u00a0par l&#8217;entr\u00e9e d&#8217;eau d&#8217;alimentation.\u00a0L&#8217;eau d&#8217;alimentation (circuit secondaire) est chauff\u00e9e de\u00a0<\/span><strong><span>~ 230 \u00b0 C 446 \u00b0 F<\/span><\/strong><span>\u00a0au point d&#8217;\u00e9bullition de ce fluide\u00a0<\/span><strong><span>(280 \u00b0 C; 536 \u00b0 F; 6,5 MPa)<\/span><\/strong><span>\u00a0.\u00a0L&#8217;eau d&#8217;alimentation est ensuite \u00e9vapor\u00e9e et la vapeur sous pression\u00a0<\/span><strong><span>(<\/span><\/strong><span>\u00a0vapeur\u00a0<strong><a title=\"Vapeur s\u00e8che\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/materials-nuclear-engineering\/properties-steam-what-is-steam\/dry-steam\/\">satur\u00e9e<\/a><\/strong><strong>\u00a0280 \u00b0 C; 536 \u00b0 F; 6,5 MPa)<\/strong>\u00a0quitte le g\u00e9n\u00e9rateur de vapeur par la sortie de vapeur et continue vers la turbine \u00e0 vapeur.<\/span><\/p>\n<p><span>h\u00a0<\/span><sub><span>II, entr\u00e9e<\/span><\/sub><span>\u00a0= 991 kJ \/ kg<\/span><\/p>\n<p><span>=&gt; \u0394h\u00a0<\/span><sub><span>II<\/span><\/sub><span>\u00a0= 1789 kJ \/ kg<\/span><\/p>\n<p><span>h\u00a0<\/span><sub><span>II, sortie<\/span><\/sub><span>\u00a0= 2780 kJ \/ kg<\/span><\/p>\n<p><strong><span>\u00c9quilibre du g\u00e9n\u00e9rateur de vapeur<\/span><\/strong><\/p>\n<p><span>\u00c9tant donn\u00e9 que la diff\u00e9rence d&#8217;enthalpies sp\u00e9cifiques est moindre pour le liquide de refroidissement primaire que pour l&#8217;eau d&#8217;alimentation, il est \u00e9vident que la quantit\u00e9 de liquide de refroidissement primaire sera sup\u00e9rieure \u00e0 1 kg.\u00a0Pour produire 1 kg de vapeur satur\u00e9e \u00e0 partir de l&#8217;eau d&#8217;alimentation, environ\u00a0<\/span><strong><span>1789\/206 x 1 kg = 8,68 kg<\/span><\/strong><span>\u00a0de liquide de refroidissement primaire est n\u00e9cessaire.<\/span><\/p>\n<\/div>\n<\/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><span>Exemple: combustion d&#8217;hydrog\u00e8ne<\/span><\/h2>\n<figure id=\"attachment_15727\" class=\"wp-caption alignright\" aria-describedby=\"caption-attachment-15727\"><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Combustion-of-Hydrogen-schematic.png\"><img loading=\"lazy\" class=\"size-medium wp-image-15727 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Combustion-of-Hydrogen-schematic-300x248.png\" alt=\"Combustion d'hydrog\u00e8ne\" width=\"300\" height=\"248\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Combustion-of-Hydrogen-schematic-300x248.png\" \/><\/a><figcaption id=\"caption-attachment-15727\" class=\"wp-caption-text\"><span>Dans une flamme d&#8217;hydrog\u00e8ne pur, br\u00fblant dans l&#8217;air, l&#8217;hydrog\u00e8ne (H2) r\u00e9agit avec l&#8217;oxyg\u00e8ne (O2) pour former de l&#8217;eau (H2O) et lib\u00e8re de l&#8217;\u00e9nergie.<\/span><\/figcaption><\/figure>\n<p><span>Consid\u00e9rez la\u00a0<\/span><strong><span>combustion de l&#8217;hydrog\u00e8ne<\/span><\/strong><span>\u00a0dans l&#8217;air.\u00a0Dans une flamme d&#8217;hydrog\u00e8ne gazeux pur, br\u00fblant dans l&#8217;air, l&#8217;\u00a0<\/span><strong><span>hydrog\u00e8ne (H\u00a0<\/span><sub><span>2<\/span><\/sub><span>\u00a0)<\/span><\/strong><span>\u00a0r\u00e9agit avec l&#8217;\u00a0\u00a0<\/span><strong><span>oxyg\u00e8ne (O\u00a0<\/span><sub><span>2<\/span><\/sub><span>\u00a0)<\/span><\/strong><span>\u00a0pour former de l&#8217;\u00a0<\/span><strong><span>eau (H\u00a0<\/span><sub><span>2<\/span><\/sub><span>\u00a0O)<\/span><\/strong><span>\u00a0et\u00a0<\/span><strong><span>lib\u00e8re de l&#8217;\u00e9nergie<\/span><\/strong><span>\u00a0.<\/span><\/p>\n<p><span>\u00c9nerg\u00e9tiquement, le processus peut \u00eatre consid\u00e9r\u00e9 comme n\u00e9cessitant de l&#8217;\u00e9nergie pour dissocier le\u00a0<\/span><strong><span>H\u00a0<\/span><sub><span>2<\/span><\/sub>\u00a0<\/strong><span>\u00a0et l&#8217;\u00a0<\/span><strong><span>O\u00a0<\/span><sub><span>2<\/span><\/sub><\/strong><span>\u00a0, mais la liaison du H\u00a0<\/span><sub><span>2<\/span><\/sub><span>\u00a0O ram\u00e8ne le syst\u00e8me \u00e0 un \u00e9tat li\u00e9 avec\u00a0<\/span><strong><span>un potentiel n\u00e9gatif<\/span><\/strong><span>\u00a0.\u00a0Il est en fait\u00a0<\/span><strong><span>plus n\u00e9gatif<\/span><\/strong><span>\u00a0que les \u00e9tats li\u00e9s des r\u00e9actifs, et la formation des deux mol\u00e9cules d&#8217;eau est donc une\u00a0<\/span><strong><span>r\u00e9action exothermique<\/span><\/strong><span>\u00a0, qui lib\u00e8re 5,7 eV d&#8217;\u00e9nergie.\u00a0En termes d&#8217;enthalpie, l&#8217;enthalpie de combustion est de -286 kJ \/ mol:<\/span><\/p>\n<p><strong><span>2H\u00a0<\/span><sub><span>2<\/span><\/sub><span>\u00a0(g) + O\u00a0<\/span><sub><span>2<\/span><\/sub><span>\u00a0(g) \u2192 2H\u00a0<\/span><sub><span>2<\/span><\/sub><span>\u00a0O (g)<\/span><\/strong><\/p>\n<p><span>En termes d&#8217;enthalpie, l&#8217;enthalpie de combustion est de -286 kJ \/ mol (\u00e9nergie par mol d&#8217;hydrog\u00e8ne mol\u00e9culaire):<\/span><\/p>\n<p><strong><span>2H\u00a0<\/span><sub><span>2<\/span><\/sub><span>\u00a0(g) + O\u00a0<\/span><sub><span>2<\/span><\/sub><span>\u00a0(g) \u2192 2H\u00a0<\/span><sub><span>2<\/span><\/sub><span>\u00a0O (l) +572 kJ<\/span><\/strong><\/p>\n<p><span>L&#8217;\u00e9quilibre \u00e9nerg\u00e9tique avant et apr\u00e8s la r\u00e9action peut \u00eatre illustr\u00e9 sch\u00e9matiquement par l&#8217;\u00e9tat dans lequel tous les atomes sont libres pris comme r\u00e9f\u00e9rence pour l&#8217;\u00e9nergie.<\/span><\/p>\n<\/div>\n<\/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><span>Exemple: enthalpie de vapeur humide<\/span><\/h2>\n<figure id=\"attachment_16026\" class=\"wp-caption alignright\" aria-describedby=\"caption-attachment-16026\"><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Thermodynamic-Cycles-min.png\"><img loading=\"lazy\" class=\"size-medium wp-image-16026 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Thermodynamic-Cycles-min-300x277.png\" alt=\"thermodynamique technique\" width=\"300\" height=\"277\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Thermodynamic-Cycles-min-300x277.png\" \/><\/a><figcaption id=\"caption-attachment-16026\" class=\"wp-caption-text\"><span>Cycle de Rankine &#8211; La thermodynamique comme science de la conversion d&#8217;\u00e9nergie<\/span><\/figcaption><\/figure>\n<p><span>Un \u00e9tage haute pression de turbine \u00e0 vapeur fonctionne \u00e0 l&#8217;\u00e9tat stable avec des conditions d&#8217;entr\u00e9e de 6 MPa, t = 275,6 \u00b0 C, x = 1 (point C).\u00a0La vapeur sort de cet \u00e9tage de turbine \u00e0 une pression de 1,15 MPa, 186 \u00b0 C et x = 0,87 (point D).\u00a0Calculez la diff\u00e9rence d&#8217;enthalpie entre ces deux \u00e9tats.<\/span><\/p>\n<p><span>L&#8217;enthalpie pour l&#8217;\u00e9tat C peut \u00eatre pr\u00e9lev\u00e9e directement dans\u00a0<\/span><a title=\"Tables \u00e0 vapeur - Propri\u00e9t\u00e9s sp\u00e9cifiques de l'eau et de la vapeur\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/steam-tables\/\"><span>les tables<\/span><\/a><span>\u00a0de\u00a0<a title=\"Tables \u00e0 vapeur - Propri\u00e9t\u00e9s sp\u00e9cifiques de l'eau et de la vapeur\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/steam-tables\/\">vapeur<\/a>\u00a0, tandis que l&#8217;enthalpie pour l&#8217;\u00e9tat D doit \u00eatre calcul\u00e9e en utilisant la qualit\u00e9 de la vapeur:<\/span><\/p>\n<p><strong><em><span>h\u00a0<\/span><\/em><\/strong><strong><em><sub><span>1, humide<\/span><\/sub><\/em><\/strong><strong><em><span>\u00a0=<\/span><\/em><\/strong><strong><span>\u00a02785 kJ \/ kg<\/span><\/strong><\/p>\n<p><strong><em><span>h\u00a0<\/span><\/em><\/strong><strong><em><sub><span>2, humide<\/span><\/sub><\/em><\/strong><strong><em><span>\u00a0= h\u00a0<\/span><\/em><\/strong><strong><em><sub><span>2, s<\/span><\/sub><\/em><\/strong><strong><em><span>\u00a0x + (1 &#8211; x) h\u00a0<\/span><\/em><\/strong><strong><em><sub><span>2, l<\/span><\/sub><\/em><\/strong><span>\u00a0\u00a0= 2782.\u00a00,87 + (1 &#8211; 0,87).\u00a0790 = 2420 + 103 =<\/span><strong><span>\u00a02523 kJ \/ kg<\/span><\/strong><\/p>\n<p><strong><span>\u0394h = 262 kJ \/ kg<\/span><\/strong><\/p>\n<\/div>\n<\/div>\n<figure id=\"attachment_16678\" class=\"wp-caption alignright\" aria-describedby=\"caption-attachment-16678\"><figcaption id=\"caption-attachment-16678\" class=\"wp-caption-text\">&#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>Cet article est bas\u00e9 sur la traduction automatique de l&#8217;article original en anglais. Pour plus d&#8217;informations, voir l&#8217;article en anglais. Pouvez vous nous aider Si vous souhaitez corriger la traduction, envoyez-la \u00e0 l&#8217;adresse: translations@nuclear-power.com ou remplissez le formulaire de traduction en ligne. Nous appr\u00e9cions votre aide, nous mettrons \u00e0 jour la traduction le plus rapidement possible. Merci<\/p>\n<\/figcaption><\/figure>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>Exemples d&#8217;enthalpie &#8211; Calcul de l&#8217;enthalpie.\u00a0Piston sans friction, bilan \u00e9nerg\u00e9tique, enthalpie sp\u00e9cifique de la vapeur humide.\u00a0Exemples et solutions.\u00a0G\u00e9nie thermique Enthalpie en unit\u00e9s extensives Propri\u00e9t\u00e9s \u00e9tendues et intensives du milieu dans le pressuriseur. H = U + pV L&#8217;enthalpie\u00a0\u00a0est une quantit\u00e9 importante, elle d\u00e9pend de la taille du syst\u00e8me ou de la quantit\u00e9 de substance qu&#8217;il &#8230; <a title=\"Exemple d&#8217;enthalpie &#8211; Calcul &#8211; D\u00e9finition\" class=\"read-more\" href=\"https:\/\/www.thermal-engineering.org\/fr\/quest-ce-quun-exemple-denthalpie-calcul-definition\/\" aria-label=\"En savoir plus sur Exemple d&#8217;enthalpie &#8211; Calcul &#8211; D\u00e9finition\">Lire la suite<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[8],"tags":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v15.4 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Exemple d&#039;enthalpie - Calcul - D\u00e9finition<\/title>\n<meta name=\"description\" content=\"Exemples d&#039;enthalpie - Calcul de l&#039;enthalpie. 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