![\"3](\"https:\/\/www.thermal-engineering.org\/wp-content\/uploads\/2024\/07\/3_loai_dan_nhiet_trong_chat_ran.png\")
<\/p>\n3 lo\u1ea1i d\u1eabn nhi\u1ec7t trong ch\u1ea5t r\u1eafn: d\u1eabn nhi\u1ec7t qua ti\u1ebfp x\u00fac, d\u1eabn nhi\u1ec7t qua d\u00f2ng nhi\u1ec7t v\u00e0 d\u1eabn nhi\u1ec7t qua khu\u1ebfch t\u00e1n nhi\u1ec7t, c\u00f9ng v\u1edbi c\u00e1c v\u00ed d\u1ee5 th\u1ef1c t\u1ebf.<\/p>\n
<\/p>\n
Trong l\u0129nh v\u1ef1c k\u1ef9 thu\u1eadt nhi\u1ec7t, hi\u1ec3u c\u00e1ch nhi\u1ec7t \u0111\u01b0\u1ee3c truy\u1ec1n qua c\u00e1c ch\u1ea5t r\u1eafn l\u00e0 r\u1ea5t quan tr\u1ecdng. C\u00f3 ba ph\u01b0\u01a1ng th\u1ee9c ch\u00ednh \u0111\u1ec3 nhi\u1ec7t \u0111\u01b0\u1ee3c d\u1eabn trong ch\u1ea5t r\u1eafn: d\u1eabn nhi\u1ec7t, \u0111\u1ed1i l\u01b0u nhi\u1ec7t v\u00e0 b\u1ee9c x\u1ea1 nhi\u1ec7t. B\u00e0i vi\u1ebft n\u00e0y s\u1ebd t\u1eadp trung v\u00e0o vi\u1ec7c gi\u1ea3i th\u00edch t\u1eebng lo\u1ea1i d\u1eabn nhi\u1ec7t trong ch\u1ea5t r\u1eafn.<\/p>\n
D\u1eabn nhi\u1ec7t l\u00e0 qu\u00e1 tr\u00ecnh m\u00e0 nhi\u1ec7t l\u01b0\u1ee3ng \u0111\u01b0\u1ee3c truy\u1ec1n t\u1eeb v\u00f9ng nhi\u1ec7t \u0111\u1ed9 cao h\u01a1n \u0111\u1ebfn v\u00f9ng nhi\u1ec7t \u0111\u1ed9 th\u1ea5p h\u01a1n trong m\u1ed9t ch\u1ea5t r\u1eafn. Qu\u00e1 tr\u00ecnh n\u00e0y x\u1ea3y ra do s\u1ef1 va ch\u1ea1m gi\u1eefa c\u00e1c ph\u00e2n t\u1eed v\u00e0 electron t\u1ef1 do. C\u00f4ng th\u1ee9c c\u01a1 b\u1ea3n c\u1ee7a d\u1eabn nhi\u1ec7t \u0111\u01b0\u1ee3c m\u00f4 t\u1ea3 b\u1edfi Lu\u1eadt Fourier:<\/p>\n
\n \\[
\n q = -k \\cdot A \\cdot \\frac{dT}{dx}
\n \\]\n<\/p>\n
Trong \u0111\u00f3:<\/p>\n
\u0110\u1ed1i l\u01b0u nhi\u1ec7t th\u01b0\u1eddng xu\u1ea5t hi\u1ec7n trong ch\u1ea5t l\u1ecfng v\u00e0 kh\u00ed, tuy nhi\u00ean, c\u0169ng c\u00f3 th\u1ec3 x\u1ea3y ra trong ch\u1ea5t r\u1eafn d\u1ea1ng h\u1ea1t ho\u1eb7c khi c\u00f3 s\u1ef1 chuy\u1ec3n \u0111\u1ed9ng c\u1ee7a m\u1ed9t ph\u1ea7n t\u1eed ch\u1ea5t r\u1eafn. Trong \u0111\u1ed1i l\u01b0u nhi\u1ec7t, nhi\u1ec7t l\u01b0\u1ee3ng \u0111\u01b0\u1ee3c truy\u1ec1n t\u1eeb v\u00f9ng nhi\u1ec7t \u0111\u1ed9 cao h\u01a1n \u0111\u1ebfn v\u00f9ng nhi\u1ec7t \u0111\u1ed9 th\u1ea5p h\u01a1n nh\u1edd s\u1ef1 di chuy\u1ec3n c\u1ee7a c\u00e1c ph\u00e2n t\u1eed trong ch\u1ea5t trung gian.<\/p>\n
C\u00f4ng th\u1ee9c t\u1ed5ng qu\u00e1t cho \u0111\u1ed1i l\u01b0u nhi\u1ec7t l\u00e0:<\/p>\n
\n \\[
\n q = h \\cdot A \\cdot (T_s – T_f)
\n \\]\n<\/p>\n
Trong \u0111\u00f3:<\/p>\n
B\u1ee9c x\u1ea1 nhi\u1ec7t l\u00e0 ph\u01b0\u01a1ng ph\u00e1p truy\u1ec1n nhi\u1ec7t th\u00f4ng qua s\u00f3ng \u0111i\u1ec7n t\u1eeb, kh\u00f4ng c\u1ea7n m\u00f4i tr\u01b0\u1eddng trung gian. \u0110\u00e2y l\u00e0 c\u00e1ch m\u00e0 nhi\u1ec7t t\u1eeb m\u1eb7t tr\u1eddi t\u1edbi tr\u00e1i \u0111\u1ea5t. C\u00f4ng th\u1ee9c b\u1ee9c x\u1ea1 nhi\u1ec7t \u0111\u01b0\u1ee3c m\u00f4 t\u1ea3 b\u1edfi \u0110\u1ecbnh lu\u1eadt Stefan-Boltzmann:<\/p>\n
\n \\[
\n E = \\sigma \\cdot T^4
\n \\]\n<\/p>\n
Trong \u0111\u00f3:<\/p>\n
Bi\u1ebft v\u00e0 hi\u1ec3u r\u00f5 c\u00e1c h\u00ecnh th\u1ee9c d\u1eabn nhi\u1ec7t kh\u00e1c nhau s\u1ebd gi\u00fap ch\u00fang ta thi\u1ebft k\u1ebf v\u00e0 c\u1ea3i ti\u1ebfn c\u00e1c h\u1ec7 th\u1ed1ng nhi\u1ec7t, t\u1eeb c\u00e1ch c\u00e1ch nhi\u1ec7t nh\u00e0 c\u1eeda \u0111\u1ebfn c\u00e1c quy tr\u00ecnh c\u00f4ng nghi\u1ec7p ph\u1ee9c t\u1ea1p.<\/p>\n","protected":false},"excerpt":{"rendered":"
3 lo\u1ea1i d\u1eabn nhi\u1ec7t trong ch\u1ea5t r\u1eafn: d\u1eabn nhi\u1ec7t qua ti\u1ebfp x\u00fac, d\u1eabn nhi\u1ec7t qua d\u00f2ng nhi\u1ec7t v\u00e0 d\u1eabn nhi\u1ec7t qua khu\u1ebfch t\u00e1n nhi\u1ec7t, c\u00f9ng v\u1edbi c\u00e1c v\u00ed d\u1ee5 th\u1ef1c t\u1ebf.<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[132],"tags":[],"yoast_head":"\n