基于三维非稳态模型的车载加油油气回收系统碳罐结构优化

Structure optimization of the carbon canister for onboard refueling vapor recovery system based on three-dimensional unsteady-state

以车载加油油气回收系统(ORVR)碳罐吸附过程的传质传热过程为研究对象,以正丁烷/氮气模拟挥发油气,采用固定床吸附实验测试和CFD数值模拟相结合的方法,结合物种转移模型、层流模型和多孔介质模型,建立了三维非稳态ORVR碳罐的数值模型,以穿透时间和温度为特征量,从腔体体积比和进出口直径两个方面对其结构进行初步优化设计。结果表明,吸附过程床层温度模拟值与实验值偏差率低于7%,双腔体体积比为5∶3时,ORVR碳罐吸附过程中温度升高值相比其他结构低0.9~1.6℃,安全性高;进出口直径为12 mm时,在吸附穿透时间和床层温度升温方面综合性能最好。本研究可为ORVR碳罐结构优化设计提供参考。

The heat and mass transfer characteristic of carbon canister for onboard refueling vapor recovery(ORVR)was investigated using the research methods,the n-butane/nitrogen gas was used to simulate volatile oil and gas,and the three-dimensional unsteady numerical model for ORVR carbon canister was established by using the methods of fixed bed adsorption test and CFD numerical simulation combined with species transfer model,laminar flow model and porous medium model.Based on adsorption penetration time and bed temperature,the structure optimization was carried out from the aspect of cavity volume ratio,inlet and outlet diameter.The results showed that the deviation rate of the simulation value and the experimental value of ORVR bed temperature was lower than 7%.When the cavity volume ratio was 5:3,the bed-temperature value increased in ORVR carbon canister was 0.9~1.6℃lower than other structures,thus the safety performance was high.When the inlet and outlet diameter was selected as 12 mm,it showed the best comprehensive performance in terms of adsorption penetration time and bed temperature rise during the adsorption process.This study can provide reference for structural optimization design of ORVR carbon tank.