納米流體導(dǎo)熱系數(shù)和強化機理的分子動力學(xué)模擬

楊鵬志++廖立

摘 要：納米流體的導(dǎo)熱系數(shù)是影響其傳熱特性的重要熱物性參數(shù)，本文采用非平衡分子動力學(xué)方法，對納米流體的導(dǎo)熱系數(shù)進行了分子動力學(xué)模擬和計算。納米流體的導(dǎo)熱系數(shù)相比于基礎(chǔ)液體有了明顯的提高，此外納米流體的導(dǎo)熱系數(shù)還會受到納米顆粒體積分?jǐn)?shù)、材料屬性、形狀、以及系統(tǒng)溫度的影響。納米流體的導(dǎo)熱系數(shù)與納米顆粒、基液、以及基液和納米顆粒之間的相互作用息息相關(guān)。通過探索和分析納米流體內(nèi)部粒子的遷移過程和動力學(xué)機理，研究納米流體內(nèi)部的能量傳遞過程以及納米流體導(dǎo)熱系數(shù)強化的微觀作用機理。納米流體微觀結(jié)構(gòu)的改變以及納米顆粒的微運動是強化納米流體導(dǎo)熱系數(shù)的主要微觀原因。

關(guān)鍵詞：非平衡分子動力學(xué)模擬；納米流體；導(dǎo)熱系數(shù)；微觀機理

The thermal conductivity and strengthening mechanism of nanofluids by molecular dynamics Simulation

Yang Pengzhi， Liao Li

（Key Laboratory of Low-grade Energy Utilization Technologies and Systems of Ministry of Education， College of Power Engineering， Chongqing University， Chongqing 400044， China）

Abstract：The thermal conductivity of nanofluids plays an important role in heat transfer， non-equilibrium RNEMD molecular dynamics method is used to calculate the thermal conductivity of nanofluids in this article. The thermal conductivity of nanofluids is enhanced to a very large degree compared to the base fluid. In addition， the volume fraction of nanopartice， the material properties， the shape of nanoparticle and the temperature are significant factors to the thermal conductivity of nanofluids. Nanopartice and the base fluid influence each other as well as the thermal conductivity of nanofluids. Researches on the energy transfer process of nanofluids and the micro mechanism of thermal conductivity enhancement of nanofluids by analyzing the migration process of nanoparticle and the dynamic mechanism of nanoparticle suggest that the change of micro structure of nanofluids and the micro motion of nanoparticle are the main reasons to affect the thermal conductivity of nanofluids.

Keywords：non-equilibrium molecular dynamics simulation；nanofluids； thermal conductivity； micro mechanism