![\"5](\"https:\/\/www.thermal-engineering.org\/wp-content\/uploads\/2024\/07\/5_loai_lop_bien_trong_co_hoc_chat_long.png\")
<\/p>\nT\u00ecm hi\u1ec3u 5 lo\u1ea1i l\u1edbp bi\u00ean trong c\u01a1 h\u1ecdc ch\u1ea5t l\u1ecfng, vai tr\u00f2 quan tr\u1ecdng c\u1ee7a ch\u00fang v\u00e0 c\u00e1ch ch\u00fang \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn hi\u1ec7u su\u1ea5t trong k\u1ef9 thu\u1eadt nhi\u1ec7t.<\/p>\n
<\/p>\n
Trong c\u01a1 h\u1ecdc ch\u1ea5t l\u1ecfng, kh\u00e1i ni\u1ec7m l\u1edbp bi\u00ean (boundary layer) r\u1ea5t quan tr\u1ecdng v\u00ec n\u00f3 quy\u1ebft \u0111\u1ecbnh nhi\u1ec1u t\u00ednh ch\u1ea5t v\u00e0 hi\u1ec7n t\u01b0\u1ee3ng di\u1ec5n ra trong d\u00f2ng ch\u1ea3y. L\u1edbp bi\u00ean l\u00e0 v\u00f9ng m\u1ecfng c\u1ee7a ch\u1ea5t l\u1ecfng g\u1ea7n b\u1ec1 m\u1eb7t n\u01a1i m\u00e0 t\u1ed1c \u0111\u1ed9 c\u1ee7a d\u00f2ng ch\u1ea3y thay \u0111\u1ed5i t\u1eeb gi\u00e1 tr\u1ecb t\u1ef1 do c\u1ee7a d\u00f2ng ch\u1ea3y v\u1ec1 zero do t\u00e1c d\u1ee5ng c\u1ee7a \u00e1p su\u1ea5t. D\u01b0\u1edbi \u0111\u00e2y l\u00e0 n\u0103m lo\u1ea1i l\u1edbp bi\u00ean ch\u00ednh trong c\u01a1 h\u1ecdc ch\u1ea5t l\u1ecfng.<\/p>\n
L\u1edbp bi\u00ean \u0111\u1ed9ng l\u1ef1c h\u1ecdc ph\u00e1t sinh do t\u00e1c \u0111\u1ed9ng c\u1ee7a l\u1ef1c ma s\u00e1t l\u00e0m gi\u1ea3m t\u1ed1c \u0111\u1ed9 d\u00f2ng ch\u1ea3y t\u1eeb gi\u00e1 tr\u1ecb c\u1ee7a d\u00f2ng ch\u1ea3y t\u1ef1 do v\u1ec1 zero t\u1ea1i b\u1ec1 m\u1eb7t. \u0110\u00e2y l\u00e0 l\u1edbp bi\u00ean ph\u1ed5 bi\u1ebfn nh\u1ea5t v\u00e0 \u0111\u01b0\u1ee3c nghi\u00ean c\u1ee9u nhi\u1ec1u trong c\u01a1 h\u1ecdc ch\u1ea5t l\u1ecfng.<\/p>\n
L\u1edbp bi\u00ean nhi\u1ec7t xu\u1ea5t hi\u1ec7n do s\u1ef1 ch\u00eanh l\u1ec7ch nhi\u1ec7t \u0111\u1ed9 gi\u1eefa b\u1ec1 m\u1eb7t v\u00e0 ch\u1ea5t l\u1ecfng xung quanh, t\u1ea1o ra m\u1ed9t gradient nhi\u1ec7t \u0111\u1ed9 trong l\u1edbp bi\u00ean. \u0110\u1ed9 d\u00e0y c\u1ee7a l\u1edbp bi\u00ean nhi\u1ec7t th\u01b0\u1eddng kh\u00e1c so v\u1edbi l\u1edbp bi\u00ean \u0111\u1ed9ng l\u1ef1c h\u1ecdc v\u00e0 ph\u1ee5 thu\u1ed9c v\u00e0o t\u00ednh ch\u1ea5t d\u1eabn nhi\u1ec7t v\u00e0 d\u1eabn nhi\u1ec7t c\u1ee7a ch\u1ea5t l\u1ecfng.<\/p>\n
L\u1edbp bi\u00ean khu\u1ebfch t\u00e1n ch\u1ea5t tan l\u00e0 do s\u1ef1 ph\u00e2n t\u00e1n c\u1ee7a m\u1ed9t ho\u1eb7c nhi\u1ec1u ch\u1ea5t tan t\u1eeb b\u1ec1 m\u1eb7t v\u00e0o trong d\u00f2ng ch\u1ea3y. \u0110\u00e2y l\u00e0 m\u1ed9t lo\u1ea1i l\u1edbp bi\u00ean quan tr\u1ecdng trong c\u00e1c qu\u00e1 tr\u00ecnh truy\u1ec1n kh\u1ed1i, ch\u1eb3ng h\u1ea1n nh\u01b0 trong qu\u00e1 tr\u00ecnh h\u1ea5p th\u1ee5 gas ho\u1eb7c trong c\u00e1c hi\u1ec7n t\u01b0\u1ee3ng khu\u1ebfch t\u00e1n.<\/p>\n
L\u1edbp bi\u00ean t\u1eeb t\u00ednh xu\u1ea5t hi\u1ec7n trong c\u00e1c d\u00f2ng ch\u1ea3y ch\u1ea5t l\u1ecfng d\u1eabn \u0111i\u1ec7n c\u00f3 t\u00e1c \u0111\u1ed9ng c\u1ee7a t\u1eeb tr\u01b0\u1eddng b\u00ean ngo\u00e0i. L\u1ef1c t\u1eeb v\u00e0 d\u00f2ng \u0111i\u1ec7n trong ch\u1ea5t l\u1ecfng t\u1ea1o ra c\u00e1c hi\u1ec7u \u1ee9ng \u0111\u1eb7c bi\u1ec7t trong l\u1edbp bi\u00ean, ch\u1eb3ng h\u1ea1n nh\u01b0 c\u00e1c d\u00f2ng ch\u1ea3y t\u1ed1i \u01b0u ho\u1eb7c c\u00e1c l\u1ef1c c\u1ea3 tu\u1ea7n ho\u00e0n.<\/p>\n
L\u1edbp bi\u00ean s\u00f3ng h\u00ecnh th\u00e0nh tr\u00ean b\u1ec1 m\u1eb7t ch\u1ea5t l\u1ecfng khi c\u00f3 s\u1ef1 t\u1ed3n t\u1ea1i c\u1ee7a s\u00f3ng ho\u1eb7c c\u00e1c x\u00e1o tr\u1ed9n c\u1ee7a b\u1ec1 m\u1eb7t. Lo\u1ea1i l\u1edbp bi\u00ean n\u00e0y th\u01b0\u1eddng g\u1eb7p \u1edf c\u00e1c nghi\u00ean c\u1ee9u v\u1ec1 bi\u1ec3n, \u0111\u1ea1i d\u01b0\u01a1ng h\u1ecdc, v\u00e0 c\u00e1c hi\u1ec7n t\u01b0\u1ee3ng li\u00ean quan \u0111\u1ebfn s\u00f3ng.<\/p>\n
Hai c\u00f4ng th\u1ee9c ph\u1ed5 bi\u1ebfn nh\u1ea5t trong vi\u1ec7c t\u00ednh to\u00e1n l\u1edbp bi\u00ean l\u00e0 ph\u01b0\u01a1ng tr\u00ecnh Navier-Stokes v\u00e0 ph\u01b0\u01a1ng tr\u00ecnh n\u0103ng l\u01b0\u1ee3ng.<\/p>\n
Ph\u01b0\u01a1ng tr\u00ecnh Navier-Stokes (vi\u1ebft \u0111\u01a1n gi\u1ea3n cho d\u00f2ng ch\u1ea3y kh\u00f4ng n\u00e9n \u0111\u01b0\u1ee3c):<\/p>\n
\\[
\n\\rho \\left( \\frac{\\partial u}{\\partial t} + u \\frac{\\partial u}{\\partial x} + v \\frac{\\partial u}{\\partial y} + w \\frac{\\partial u}{\\partial z} \\right) = -\\frac{\\partial p}{\\partial x} + \\mu \\left( \\frac{\\partial^2 u}{\\partial x^2} + \\frac{\\partial^2 u}{\\partial y^2} + \\frac{\\partial^2 u}{\\partial z^2} \\right)
\n\\]\n
Ph\u01b0\u01a1ng tr\u00ecnh n\u0103ng l\u01b0\u1ee3ng (\u0111\u1ed1i v\u1edbi d\u1eabn nhi\u1ec7t):<\/p>\n
\\[
\n\\rho c_p \\left( \\frac{\\partial T}{\\partial t} + u \\frac{\\partial T}{\\partial x} + v \\frac{\\partial T}{\\partial y} + w \\frac{\\partial T}{\\partial z} \\right) = k \\left( \\frac{\\partial^2 T}{\\partial x^2} + \\frac{\\partial^2 T}{\\partial y^2} + \\frac{\\partial^2 T}{\\partial z^2} \\right)
\n\\]\n
Hi v\u1ecdng b\u00e0i vi\u1ebft n\u00e0y \u0111\u00e3 gi\u00fap b\u1ea1n hi\u1ec3u h\u01a1n v\u1ec1 c\u00e1c lo\u1ea1i l\u1edbp bi\u00ean trong c\u01a1 h\u1ecdc ch\u1ea5t l\u1ecfng v\u00e0 t\u1ea7m quan tr\u1ecdng c\u1ee7a ch\u00fang trong c\u00e1c nghi\u00ean c\u1ee9u v\u00e0 \u1ee9ng d\u1ee5ng th\u1ef1c t\u1ebf.<\/p>\n","protected":false},"excerpt":{"rendered":"
T\u00ecm hi\u1ec3u 5 lo\u1ea1i l\u1edbp bi\u00ean trong c\u01a1 h\u1ecdc ch\u1ea5t l\u1ecfng, vai tr\u00f2 quan tr\u1ecdng c\u1ee7a ch\u00fang v\u00e0 c\u00e1ch ch\u00fang \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn hi\u1ec7u su\u1ea5t trong k\u1ef9 thu\u1eadt nhi\u1ec7t.<\/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