{"id":2424,"date":"2016-03-14T14:27:10","date_gmt":"2016-03-14T14:27:10","guid":{"rendered":"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/?p=2424"},"modified":"2016-03-14T14:27:10","modified_gmt":"2016-03-14T14:27:10","slug":"power-and-refriger-a-tion-cyclesthe-brayton-cycle-with-regeneration","status":"publish","type":"post","link":"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/power-and-refriger-a-tion-cyclesthe-brayton-cycle-with-regeneration\/","title":{"rendered":"POWER AND REFRIGER A TION CYCLES:THE BRAYTON CYCLE WITH REGENERATION"},"content":{"rendered":"<div class=\"ndzer6a0dce4ef3c5f\" ><script type=\"text\/javascript\">\n\tatOptions = {\n\t\t'key' : '61e5902552e2353963d8d2f1bd1f4a8f',\n\t\t'format' : 'iframe',\n\t\t'height' : 250,\n\t\t'width' : 300,\n\t\t'params' : {}\n\t};\n<\/script>\n<script type=\"text\/javascript\" src=\"\/\/www.highperformanceformat.com\/61e5902552e2353963d8d2f1bd1f4a8f\/invoke.js\"><\/script><\/div><style type=\"text\/css\">\r\n@media screen and (min-width: 1201px) {\r\n.ndzer6a0dce4ef3c5f {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 993px) and (max-width: 1200px) {\r\n.ndzer6a0dce4ef3c5f {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 769px) and (max-width: 992px) {\r\n.ndzer6a0dce4ef3c5f {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 768px) and (max-width: 768px) {\r\n.ndzer6a0dce4ef3c5f {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (max-width: 767px) {\r\n.ndzer6a0dce4ef3c5f {\r\ndisplay: block;\r\n}\r\n}\r\n<\/style>\r\n<h3 align=\"justify\"><font size=\"5\">\u25a0 <b>TH<\/b><b>E BRAYTON CYCLE WITH REGENERATION<\/b><\/font><\/h3>\n<p align=\"justify\"><font size=\"5\">In gas-turbine engines, the temperature of the exhaust gas leaving the turbine is often considerably higher than the temperature of the air leaving the com<\/font><font size=\"5\">pressor. Therefore, the high-pressure air leaving the compressor can be heated by transferring heat to it from the hot exhaust gases in a counter-flow heat ex- changer, which is also known as a <i>r<\/i><i>egenerato<\/i><i>r <\/i>or a <i>r<\/i><i>ecuperato<\/i><i>r<\/i><i>. <\/i>A sketch of <\/font><font size=\"5\">the gas-turbine engine utilizing a regenerator and the <i>T<\/i><i>-s <\/i>diagram of the new <\/font><font size=\"5\">cycle are shown in Figs. 8\u201334 and 8\u201335, respectively.<\/font><\/p>\n<p align=\"justify\"><font size=\"5\">The thermal efficiency of the Brayton cycle increases as a result of regeneration since the portion of energy of the exhaust gases that is normally rejected to the surroundings is now used to preheat the air entering the combustion <\/font><font size=\"5\">chamber. This, in turn, decreases the heat input (thus fuel) requirements for the same net work output. Note, however, that the use of a regenerator is rec<\/font><font size=\"5\">ommended only when the turbine exhaust temperature is higher than the compressor exit temperature. Otherwise, heat will flow in the reverse direction (<i>to <\/i><\/font><font size=\"5\">the exhaust gases), decreasing the efficiency. This situation is encountered in gas-turbine engines operating at very high pressure ratios.<\/font> <\/p>\n<p align=\"justify\"><font size=\"5\">The highest temperature occurring within the regenerator is <i>T<\/i>4, the temperature of the exhaust gases leaving the turbine and entering the regenerator. Under no conditions can the air be preheated in the regenerator to a temperature above this value. Air normally leaves the regenerator at a lower temperature, <i>T<\/i>5. In the limiting (ideal) case, the air will exit the regenerator at the inlet temperature of the exhaust gases <i>T<\/i>4. Assuming the regenerator to be well insulated and any changes in kinetic and potential energies to be negligible, the actual and maximum heat transfers from the exhaust gases to the air can be expressed as<\/font> <\/p>\n<p align=\"justify\"><font size=\"5\"><a href=\"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-content\/uploads\/2016\/03\/POWER-AND-REFRIGERATION-CYCLES-0328.jpg\"><img decoding=\"async\" loading=\"lazy\" style=\"background-image: none; border-bottom: 0px; border-left: 0px; margin: 0px auto; padding-left: 0px; padding-right: 0px; display: block; float: none; border-top: 0px; border-right: 0px; padding-top: 0px\" title=\"POWER AND REFRIGERATION CYCLES-0328\" border=\"0\" alt=\"POWER AND REFRIGERATION CYCLES-0328\" src=\"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-content\/uploads\/2016\/03\/POWER-AND-REFRIGERATION-CYCLES-0328_thumb.jpg\" width=\"194\" height=\"207\"><\/a><a href=\"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-content\/uploads\/2016\/03\/POWER-AND-REFRIGERATION-CYCLES-0329.jpg\"><img decoding=\"async\" loading=\"lazy\" style=\"background-image: none; border-bottom: 0px; border-left: 0px; margin: 0px auto; padding-left: 0px; padding-right: 0px; display: block; float: none; border-top: 0px; border-right: 0px; padding-top: 0px\" title=\"POWER AND REFRIGERATION CYCLES-0329\" border=\"0\" alt=\"POWER AND REFRIGERATION CYCLES-0329\" src=\"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-content\/uploads\/2016\/03\/POWER-AND-REFRIGERATION-CYCLES-0329_thumb.jpg\" width=\"373\" height=\"153\"><\/a><\/font> <\/p>\n<p align=\"justify\"><font size=\"5\">A regenerator with a higher effectiveness will obviously save a greater amount of fuel since it will preheat the air to a higher temperature prior to combustion. However, achieving a higher effectiveness requires the use of a larger regenerator, which carries a higher price tag and causes a larger pressure drop. Therefore, the use of a regenerator with a very high effectiveness cannot be justified economically unless the savings from the fuel costs exceed the additional expenses involved. The effectiveness of most regenerators used in practice is below 0.85.<\/font> <\/p>\n<p align=\"justify\"><font size=\"5\">Under the cold-air-standard assumptions, the thermal efficiency of an ideal Brayton cycle with regeneration is<\/font> <\/p><div class=\"fgdkk6a0dce4ef3e8b\" ><script type=\"text\/javascript\">\n\tatOptions = {\n\t\t'key' : '0c1eb4c533eaedb7b996f49a5a4983a9',\n\t\t'format' : 'iframe',\n\t\t'height' : 300,\n\t\t'width' : 160,\n\t\t'params' : {}\n\t};\n<\/script>\n<script type=\"text\/javascript\" src=\"\/\/www.highperformanceformat.com\/0c1eb4c533eaedb7b996f49a5a4983a9\/invoke.js\"><\/script><\/div><style type=\"text\/css\">\r\n@media screen and (min-width: 1201px) {\r\n.fgdkk6a0dce4ef3e8b {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 993px) and (max-width: 1200px) {\r\n.fgdkk6a0dce4ef3e8b {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 769px) and (max-width: 992px) {\r\n.fgdkk6a0dce4ef3e8b {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 768px) and (max-width: 768px) {\r\n.fgdkk6a0dce4ef3e8b {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (max-width: 767px) {\r\n.fgdkk6a0dce4ef3e8b {\r\ndisplay: block;\r\n}\r\n}\r\n<\/style>\r\n<div class=\"dicyr6a0dce4ef3d73\" ><script async src=\"https:\/\/pagead2.googlesyndication.com\/pagead\/js\/adsbygoogle.js?client=ca-pub-0778475562755157\"\n     crossorigin=\"anonymous\"><\/script>\n<!-- 300x600 hydraulics-and-pneumatics -->\n<ins class=\"adsbygoogle\"\n     style=\"display:inline-block;width:300px;height:600px\"\n     data-ad-client=\"ca-pub-0778475562755157\"\n     data-ad-slot=\"3735577695\"><\/ins>\n<script>\n     (adsbygoogle = window.adsbygoogle || []).push({});\n<\/script><\/div><style type=\"text\/css\">\r\n@media screen and (min-width: 1201px) {\r\n.dicyr6a0dce4ef3d73 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 993px) and (max-width: 1200px) {\r\n.dicyr6a0dce4ef3d73 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 769px) and (max-width: 992px) {\r\n.dicyr6a0dce4ef3d73 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (min-width: 768px) and (max-width: 768px) {\r\n.dicyr6a0dce4ef3d73 {\r\ndisplay: block;\r\n}\r\n}\r\n@media screen and (max-width: 767px) {\r\n.dicyr6a0dce4ef3d73 {\r\ndisplay: block;\r\n}\r\n}\r\n<\/style>\r\n\n<p align=\"justify\"><font size=\"5\"><a href=\"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-content\/uploads\/2016\/03\/POWER-AND-REFRIGERATION-CYCLES-0330.jpg\"><img decoding=\"async\" loading=\"lazy\" style=\"background-image: none; border-bottom: 0px; border-left: 0px; margin: 0px auto; padding-left: 0px; padding-right: 0px; display: block; float: none; border-top: 0px; border-right: 0px; padding-top: 0px\" title=\"POWER AND REFRIGERATION CYCLES-0330\" border=\"0\" alt=\"POWER AND REFRIGERATION CYCLES-0330\" src=\"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-content\/uploads\/2016\/03\/POWER-AND-REFRIGERATION-CYCLES-0330_thumb.jpg\" width=\"259\" height=\"35\"><\/a><a href=\"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-content\/uploads\/2016\/03\/POWER-AND-REFRIGERATION-CYCLES-0331.jpg\"><img decoding=\"async\" loading=\"lazy\" style=\"background-image: none; border-bottom: 0px; border-left: 0px; margin: 0px auto; padding-left: 0px; padding-right: 0px; display: block; float: none; border-top: 0px; border-right: 0px; padding-top: 0px\" title=\"POWER AND REFRIGERATION CYCLES-0331\" border=\"0\" alt=\"POWER AND REFRIGERATION CYCLES-0331\" src=\"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-content\/uploads\/2016\/03\/POWER-AND-REFRIGERATION-CYCLES-0331_thumb.jpg\" width=\"194\" height=\"453\"><\/a><\/font> <\/p>\n<p align=\"justify\"><font size=\"5\">Therefore, the thermal efficiency of an ideal Brayton cycle with regeneration depends on the ratio of the minimum to maximum temperatures as well as the pressure ratio. The thermal efficiency is plotted in Fig. 8\u201336 for various pressure ratios and minimum-to-maximum temperature ratios. This figure shows that regeneration is most effective at lower pressure ratios and low minimum- to-maximum temperature ratios.<\/font> <\/p>\n<p align=\"justify\"><font size=\"5\"><a href=\"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-content\/uploads\/2016\/03\/POWER-AND-REFRIGERATION-CYCLES-0332.jpg\"><img decoding=\"async\" loading=\"lazy\" style=\"background-image: none; border-bottom: 0px; border-left: 0px; margin: 0px auto; padding-left: 0px; padding-right: 0px; display: block; float: none; border-top: 0px; border-right: 0px; padding-top: 0px\" title=\"POWER AND REFRIGERATION CYCLES-0332\" border=\"0\" alt=\"POWER AND REFRIGERATION CYCLES-0332\" src=\"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-content\/uploads\/2016\/03\/POWER-AND-REFRIGERATION-CYCLES-0332_thumb.jpg\" width=\"351\" height=\"126\"><\/a><a href=\"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-content\/uploads\/2016\/03\/POWER-AND-REFRIGERATION-CYCLES-0333.jpg\"><img decoding=\"async\" loading=\"lazy\" style=\"background-image: none; border-bottom: 0px; border-left: 0px; margin: 0px auto; padding-left: 0px; padding-right: 0px; display: block; float: none; border-top: 0px; border-right: 0px; padding-top: 0px\" title=\"POWER AND REFRIGERATION CYCLES-0333\" border=\"0\" alt=\"POWER AND REFRIGERATION CYCLES-0333\" src=\"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-content\/uploads\/2016\/03\/POWER-AND-REFRIGERATION-CYCLES-0333_thumb.jpg\" width=\"408\" height=\"249\"><\/a><\/font> <\/p>\n<p align=\"justify\">\n<p align=\"justify\"><font size=\"5\"><\/font> <\/p>\n<p align=\"justify\"><font size=\"5\"><\/font><\/p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u25a0 THE BRAYTON CYCLE WITH REGENERATION In gas-turbine engines, the temperature of the exhaust gas leaving the turbine is often considerably higher than the temperature of the air leaving the compressor. Therefore, the high-pressure air leaving the compressor can be heated by transferring heat to it from the hot exhaust gases in a counter-flow heat [&hellip;]<br \/><a href=\"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/power-and-refriger-a-tion-cyclesthe-brayton-cycle-with-regeneration\/\" class=\"more-link\" >Continue reading&#8230;<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[1],"tags":[],"_links":{"self":[{"href":"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-json\/wp\/v2\/posts\/2424"}],"collection":[{"href":"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-json\/wp\/v2\/comments?post=2424"}],"version-history":[{"count":1,"href":"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-json\/wp\/v2\/posts\/2424\/revisions"}],"predecessor-version":[{"id":2425,"href":"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-json\/wp\/v2\/posts\/2424\/revisions\/2425"}],"wp:attachment":[{"href":"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-json\/wp\/v2\/media?parent=2424"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-json\/wp\/v2\/categories?post=2424"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/machineryequipmentonline.com\/hydraulics-and-pneumatics\/wp-json\/wp\/v2\/tags?post=2424"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}