One- and Three-Dimensional CFD Study of an Onboard Refuelling Vapour Recovery System
Typ
Examensarbete för masterexamen
Program
Applied mechanics (MPAME), MSc
Publicerad
2020
Författare
JOHANSSON, HENRIK
WIKSTRÖM, ANDREAS
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
The human impact of the environmental development is without doubt one of the
biggest challenges in modern society. The influence from cars is highly debated and
especially the impact from fossil fuels like gasoline. At the Fuel System Department
at Volvo Cars in Torslanda, the refuelling process of the cars is tested with physical
experiments on a daily basis. A system called Onboard Refuelling Vapour Recovery
(ORVR) works within the fuel system to prevent hydrocarbons and other harmful
particles to escape during refuelling. Countries set different limitations on what
quantity of particles that may be emitted and it is sometimes difficult to explain
what causes variations in the results of the experiments. Computational fluid dynamics
(CFD) is used in order to get a more detailed view of the ORVR system,
which could be a great complement to physical experiments. Decisive parameters
for the flow field could then be evaluated and possible sources of errors of the testing
could be discovered.
In this thesis the ORVR system is studied through both one- and three-dimensional
computational fluid dynamics. The studied refuelling system corresponds to the fuel
system for a Volvo XC90 certified for the US market, with a 71 liters fuel tank. The
three dimensional case is simulated in SIEMENS Star-CCM+. The simulation uses
the Volume of Fluid (VOF) model for surface tracking of the multiphase problem.
An evaporation model is implemented to deal with the mass transfer between the
phases. The accuracy of the rate of evaporation of the gasoline is studied by both
experimental and computational testing.
Since the three-dimensional simulations are computationally expensive and time
consuming, a one-dimensional study is also performed, where the software GT-Suite
is used. The geometry is discretized from the three-dimensional CAD models to a
one-dimensional system using softwares like ANSA, GT SpaceClaim and GEM3D
before being imported into GT-Suite.
The results from the different approaches are then evaluated and compared with
experimental data. Possible advantages and drawbacks with the respective methods
are analyzed and presented in a perspicuous way to the company.
Beskrivning
Ämne/nyckelord
Evaporation , ORVR , CFD , Star-CCM+ , GT-Suite , Gasoline , Refuelling , Multiphase flow , Emissions , Fuel system