{"id":2263,"date":"2024-03-17T14:21:29","date_gmt":"2024-03-17T14:21:29","guid":{"rendered":"https:\/\/news.talkwithrattan.com\/index.php\/2024\/03\/17\/a-theory-linking-ignition-with-flame-provides-roadmap-to-better-combustion-engines\/"},"modified":"2024-03-17T14:21:29","modified_gmt":"2024-03-17T14:21:29","slug":"a-theory-linking-ignition-with-flame-provides-roadmap-to-better-combustion-engines","status":"publish","type":"post","link":"https:\/\/news.talkwithrattan.com\/index.php\/2024\/03\/17\/a-theory-linking-ignition-with-flame-provides-roadmap-to-better-combustion-engines\/","title":{"rendered":"A theory linking ignition with flame provides roadmap to better combustion engines"},"content":{"rendered":"
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In a study published on January 18, 2024 in the journal Physics of Fluids<\/em>, researchers from Tohoku University theoretically linked ignition and deflagration in a combustion system, unlocking new configurations for stable, efficient combustion engines due to the possible existence of any number of steady-state solutions.<\/p>\n

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“This research directly tackles the challenge of reducing carbon dioxide emissions by enhancing the efficiency of combustion engines, a significant source of these emissions,” said Youhi Morii from the Institute of Fluid Science at Tohoku University.<\/p>\n

“A better understanding of combustion dynamics will also support the development of safer, more sustainable engineering solutions,” said Kaoru Maruta, also from the Institute of Fluid Science.<\/p>\n

Combustion dynamics involves complex coupled fluid and chemical reactions. Researchers use computational fluid dynamics to help them better understand and control the process.<\/p>\n

If a system that operates stably in a steady state and has a certain tolerance range for small perturbations can be utilized, it would simplify the structure and control of combustors, and increase the feasibility of commercializing new combustor designs.<\/p>\n

To explore this concept, the Tohoku University researchers considered a simple, one-dimensional reactive flow system, where unburned premixed gas enters a combustion chamber from the left inlet boundary, while burned gas, or deflagration wave, exits from the right outlet boundary.<\/p>\n

The working theory up to this point held that a steady-state solution exists only when the inlet velocity matches either the velocity of the deflagration wave (which travels at subsonic speeds) or the velocity of the detonation wave — a shock reaction where the exiting flames travel at supersonic speeds.<\/p>\n

However, this conventional wisdom is predicated on the assumption that chemical reactions in the preheating zone are negligible. Recent studies emphasize the significance of what’s called “autoignition-assisted flames,” wherein a deflagration propagating in a hot unburned premixed gas mixture has a faster propagation speed with the help of chemical reactions in front of the flame. This suggests that there are any number of steady-state solutions, which affect the amount of residence time gas stays in front of the deflagration.<\/p>\n

Building on these findings, the Tohoku University researchers designed a theory that successfully bridged the gap between ignition and deflagration waves, revealing the existence of additional steady-state solutions that are possible when they considered the “autoignitive reaction wave” — a wave that is affected by ignition in the preheat zone but behaves like a deflagration wave.<\/p>\n

“Contrary to the prevailing view that only a single steady-state solution exists for deflagration waves in subsonic one-dimensional systems, our approach posits an infinite number of such solutions as autoignitive reaction waves, asserting that ignition and flame are intrinsically linked,” Morii said.<\/p>\n

This means that steady-state solutions exist not merely at the two points where the inlet velocity matches the velocities of the deflagration or detonation waves, but also in a broader region if autoignitive conditions are considered.<\/p>\n

The team further extended the theory to scenarios involving supersonic inlet velocities. In the supersonic regime, the conventional understanding is that a steady-state solution is possible only when the inlet velocity matches the detonation wave velocity. However, given that the autoignitive reaction wave originates from zero-dimensional ignition, the researchers argued that it should be independent of the inlet velocity.<\/p>\n

“We propose that an infinite number of steady-state solutions exist for the autoignitive reaction wave, even in supersonic conditions,” Morii said.<\/p>\n

By theoretically linking ignition and flame, the engine can now be considered from a new perspective. Accounting for ignition phenomena offers the possibility of more stable combustion, leading to the idea of a new concept of engine that is more efficient than the conventional one.<\/p>\n

“This work on stabilizing autoignitive reaction waves marks a fundamental breakthrough, potentially revolutionizing the design of combustion systems, especially in the realm of supersonic combustion,” Morii said.<\/p>\n

While theoretical and numerical results have provided a new engine concept, it has not yet been experimentally verified. The team, therefore, plans to apply the research findings to an actual engine through further experimental verification through joint research.<\/p>\n<\/div>\n

<\/p>\n","protected":false},"excerpt":{"rendered":"

In a study published on January 18, 2024 in the journal Physics of Fluids, researchers from Tohoku University theoretically linked ignition and deflagration in a combustion system, unlocking new configurations for stable, efficient combustion engines due to the possible existence of any number of steady-state solutions. “This research directly tackles the challenge of reducing carbon […]<\/p>\n","protected":false},"author":2,"featured_media":2264,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"tdm_status":"","tdm_grid_status":"","fifu_image_url":"https:\/\/www.sciencedaily.com\/images\/scidaily-icon.png","fifu_image_alt":"","footnotes":""},"categories":[606],"tags":[4032,4033,4030,4029,4028,4026,4031,4027],"amp_enabled":true,"_links":{"self":[{"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/posts\/2263"}],"collection":[{"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/comments?post=2263"}],"version-history":[{"count":1,"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/posts\/2263\/revisions"}],"predecessor-version":[{"id":2265,"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/posts\/2263\/revisions\/2265"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/media\/2264"}],"wp:attachment":[{"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/media?parent=2263"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/categories?post=2263"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/tags?post=2263"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}