Molecular Dynamics Simulation Study On The Viscosity Properties Of Sub/Supercritical Aviation Kerosene

Aviation kerosene is a commonly used propellant in propulsion and power generation systems.It can be used for both the combustion of energy production and the regenerative cooling of key propulsion components.Accurate assessment of the thermophysical properties of aviation kerosene,including its density,viscosity and self-diffusion,is the premise of theoretical analysis and numerical simulation of various heat transfer processes in combustion chambers and regenerative cooling systems.In the design and development process,there are many heat transfer processes,such as the combustion of the combustion chamber,the transportation of fuel in the pipe,and the cooling of the engine,which usually occur at a sub/supercritical pressure higher than that of the hydrocarbon fuel.Accurate calculation of the thermophysical properties under subcritical/supercritical pressure is conducive to the efficient use of aviation kerosene and the improvement of engine efficiency.Viscosity is not only an important transportation performance of aviation kerosene,but also an important basic parameter for the research of turbocharged engine cold storage system.Based on the RP-3 aviation kerosene single-component alternative fuel model,this paper uses molecular dynamics methods to study the viscosity characteristics of n-decane(C₁₀H₂₂),n-undecane(C₁₁H₂₄)and n-dodecane(C₁₂H₂₆).The main research work is And the conclusion is as follows:First,the molecular dynamics（MD）method is used to calculate the thermophysical properties of linear alkanes under different force fields,such as viscosity and density.The results show that the COMPASS force field is compared with the other five classical force fields（AMBER,OPLS-AA,L-OPLS,Tra PPE-UA and SKS）have high accuracy in calculating viscosity and density.Then,through molecular dynamics（MD）simulation to study the viscosity characteristics of n-decane(C₁₀H₂₂),n-undecane(C₁₁H₂₄)and n-dodecane(C₁₂H₂₆)to find the best RP-3 aviation kerosene single-component replacement fuel and force field.The results show that the prediction of viscosity characteristics of C₁₁H₂₄ instead of domestic RP-3 aviation kerosene is in good agreement with the experimental data,and the prediction accuracy is higher than that of n-decane or n-dodecane;and the domestic RP-3 under subcritical pressure is calculated.For the viscosity of aviation kerosene,compare the results with the experimental data.Secondly,the self-diffusion coefficient and radial distribution function of n-undecane are calculated by MD simulation to better understand the viscosity characteristics of the sub/supercritical region at the molecular level.Finally,the Stokes-Einstein（S-E）and Rouse Model theory are used to calculate the viscosity-temperature relationship of n-undecane under subcritical/supercritical conditions.The results show that,compared with MD simulation,Stokes-Einstein（S-E）and Rouse Model theoretical calculations The viscosity of C₁₁H₂₄ is very different from the experimental value.This research has certain reference value for studying the thermophysical properties of aviation kerosene and the practical application system of scramjet.