Numerical simulation of gasoline evaporation in refueling process

Introduction

Organic vapor is generated during gasoline evaporation in vehicle refueling process, which results in huge energy waste and environmental pollution. Every year, the economic loss caused by the evaporation of gasoline is billion yuan,¹ and the vapor generated by the evaporation of gasoline will cause ozone pollution. Therefore, how to effectively control organic vapor emissions of gasoline has been widespread concern. From the 70s of the last century, many organic vapor recovery technologies have been widely studied, and the results are very limited in the study of the characteristics of mass transfer in gasoline evaporation process which is the basis of reasonable design of organic vapor recovery equipments.

At present, most experimental researches focus on the static state of gasoline evaporation and the change in evaporation rate with time,^2,3 and the experimental study of dynamic process of gasoline evaporation and evaporation rate is quite difficult, so most researches on the evaporation characteristics of gasoline refueling process use numerical methods. Banerjee and colleagues^4–6 studied the automobile refueling nozzle, gas pipe, the flow characteristics in the tank for large passenger car, and light truck loading process using volume-of-fluid (VOF) method for tracking the gas–liquid interface, but did not consider the gasoline evaporation process. Then, Banerjee^7,8 simulated the evaporation process of methanol and isooctane mixtures from the opposite direction through an inclined tube. The evaporation rate was calculated based on Fick’s law. The diffusion problem in gas phase was considered, but the interfacial convective mass transfer was ignored. Hassanvand et al.⁹ studied the turbulent process with gasoline evaporation using computational fluid dynamics (CFD) technology, but using the averaged property of gasoline makes the calculation of gasoline evaporation process far away from the real situation. Therefore, the difficulties in numerical simulation of filling process of gasoline evaporation are the reasonable selection of gasoline substitutes, gas–liquid mass transfer model, and the two-phase flow interface tracking method.

The composition of gasoline has no definite conclusion which brings difficulties to the relevant numerical simulation. The gasoline-averaged physical parameters^9,10 or key components in place of real gasoline were used to simplify the calculation.¹¹ Al Qubeissi et al.¹² used isooctane or averaged physical parameters as an alternative to gasoline and compared the oil droplet...