封闭腔内MWCNT纳米流体自然对流传热的数值模拟

Numerical simulation of natural convection and heat transfer of MWCNT nanofluids in a closure

采用Fluent软件对封闭腔内纳米流体层流自然对流换热进行了数值模拟研究.重点分析了Ra数和纳米颗粒的体积分数对自然对流换热特性的影响.数值模拟结果表明:在机油中添加多壁碳纳米管(MWCNT)粒子并没有提高基液的自然对流传热特性;对于给定的Ra数下,随着纳米颗粒体积分数的增大,纳米流体的传热特性也随之减弱;对于给定的体积分数,随着Ra数的增大,纳米流体的传热特性显著增强,但纳米流体的传热性能比机油的要弱,且在同一体积分数下随着Ra数的增大,传热性能减弱的程度要减小.

The natural convection of MWCNT-engine oil nanofluids in a two-dimensional closure was numerically simulated with FLUENT software. The effect of the Rayleigh number and the volume fraction on the heat transfer properties were investigated. The results indicate that the utilization of multi-walled carbon nanotubes （MWCNT） had no improvement to the natural convection heat transfer characteristics of the base liquid. The increase of the volume fraction can weaken the heat transfer at any given Rayleigh number∽ and the increase of the Rayleigh number can enhance the heat transfer at any given volume fraction but the heat transfer properties of nanofluids are weaker than engine oil. The increase of the Rayleigh number can decrease the degree of weakness.