Road-Vehicle Aero-Dynamics and Thermal Management

• Development of sustainable and environmentally friendly road going vehicles.

• Understand flow phenomena for minimizing emissions and fuel consumption.

• Drag- and Lift minimization.

• Cooling-Drag minimization.

• Engine-Bay thermal mangement.

• Collaboration with national and international OEMs and research organisations.

• Tools; CFD simulations and Full-Size Wind tunnel experiments

Staff: Professors (2) and Engineers (1) Ph. D. students (7) Over 20 Journal and conference papers published during 2012/13 Contact: Professor Lennart Löfdahl, Professor Simone Sebben, lennart.lofdahl@chalmers.se simone.sebben@volvocars.com

Road-Vehicle Aero-Dynamics and Thermal Management

Currently on-Going projects:

• Increased Energy Efficiency on Passenger Cars through Optimized Cooling Flow Combined with Efficient Wheel and Underbody Aerodynamics

• Encapsulation of engine bay for active thermal control and lower noise

• Complete Vehicle Airflow – New Vehicle Architecture

• Drag Reduction on Passenger Vehicles

• Investigation of angled heat exchangers for heavy vehicles

• Improved Prediction of Flow Separation for Road Vehicles

• Reducing aerodynamic drag of road vehicles by cooling airflow control and improved wheel designs

Research Motivating Problem: Aerodynamics plays an important role in road vehicle design since it offers a possibility of getting a reduction in fuel consumption and emission levels. One of the important areas is the wheel-houses, that can be responsible for up to 25-30% of total aerodynamic resistance of a vehicle.

Increased Energy Efficiency on Passenger Cars through Optimized Cooling Flow Combined with Efficient Wheel

and Underbody Aerodynamics

Alexey Vdovin

Time <2011-07> .. <2015-07>

Customers / partners:

Volvo Car Corporation

Funder: Swedish Energy Agency

Advisor: Lennart Löfdahl, Simone Sebben

Deliverable(s): • Methods to measure and decrease ventilation resistance moment without affecting aerodynamic drag force of

the vehicle.

Research question(s): • How does one measure ventilation

resistance moment in wind tunnel and in CFD?

• What are the design parameters that affect ventilation resistance?

Blago Minovski

Encapsulation of engine bay for active thermal control and lower noise Research Motivating Problem: The project addresses the growing demands for fuel efficiency and low noise emissions in trucks. It also gives room for development of more energy-efficient strategies to reduce total energy consumption of the vehicle.

Envisioned product/solution: • Software toolset for simulating the functional integration of noise and thermal shields

isolating the engine from the environment.

Research question(s): • What is the best way to simulate the system? What software tools are applicable and

which is the most efficient way to combine them.

Deliverable(s): • Method for drive-cycle simulations of vehicle’s

thermal and noise phenomena with focus on overall energy efficiency.

Time 2013.07 – 2016.12

Customers / partners:

Volvo GTT, Chalmers, Volvo CC, Scania

Funder: Vinnova, FFI

Advisor: Lennart Löfdahl

Helena Martini

Complete Vehicle Airflow – New Vehicle Architecture

Research question: By extending the cab forwards, creating a more aerodynamic shape of the tractor: • How can the aerodynamics and cooling performance be

improved by ducted inlets and outlets of the cooling airflow?

<photo of main person (usually PhD

student)>

Time 2009.09 – 2015.03 (Lic. 2011.11)

Partners: Volvo GTT, Chalmers

Funder: FFI

Advisor: Lennart Löfdahl

Research Motivating Problem: The flow through the cooling system and the underhood area is a substantial contributor to the total aerodynamic drag. A steadily increasing cooling demand further emphasizes the importance of improving the cooling airflow. With a new EU legislation, it may be permitted to elongate the cab for, for example, aerodynamic improvements. This opens up for a more innovative layout of the components in the engine bay of the truck and potential for reduced total driving resistance is seen.

Deliverable: • Improved method for combined simulations of cooling performance and aerodynamic resistance

Lennert Sterken

Drag Reduction on Passenger Vehicles Research Motivating Problem: Aerodynamics plays an essential role in the total driving resistance and hence fuel consumption of vehicles. New upcoming legislations on permissible CO2 – emissions and increasing fuel prices will push vehicle manufacturers to develop vehicles with a low fuel consumption. As a consequence the aerodynamic resistance has to be further reduced.

Research Question: • How can the rear wake be controlled and optimized such that air resistance is reduced

and that fuel consumption and CO2 – emissions are lowered?

Deliverable(s): • Improved understanding of wake structures affecting aerodynamic forces and how to

control the structures to reduce drag, while maintaining stability. • Improvement of experimental and numerical methodology for unsteady flow

investigations.

Time 2011.01 – 2015.06

Customers / partners:

Volvo Car Group, Chalmers

Funder: Vinnova, FFI

Advisor: Simone Sebben, PhD; Tim Walker and Professor Lennart Löfdahl

Lisa Henriksson

Investigation of angled heat exchangers for heavy vehicles

Time 2009.09 – 2015.03

Customers / partners:

Volvo GTT, Chalmers

Funder: FFI

Advisor: Lennart Löfdahl, Erik Dahl, Peter Gullberg

Research Motivating Problem: The cooling demand for heavy vehicles has increased and the cooling package placed in the front can not deliver the required amount of cooling.

Envisioned product/solution: • Install an angled heat exchanger to increase the heat

transfer rate.

Research question(s): • What is the most suitable heat exchanger angle to

obtain a low pressure drop over it and to increase the heat transfer rate?

Deliverable(s): • Which angle the heat exchanger should be mounted in

a vehicle. • A method to simulate pressure drop and heat transfer

rate for angled heat exchangers, in 1D and 3D.

Research Motivating Problem: The increasing fuel prices and the current discussions about CO2 reduction and sustainable act engage the policy, companies and society. An improved understanding of flow separation makes it possible to predict and control losses. This leads to a lower aerodynamic drag and with it to less fuel consumption.

Envisioned product/solution: • Improved prediction of flow separation • Applicable measurement methods for the industry • Improved results from the CFD simulations

Research question(s): • How can separation be described? (mathematical physical models) • How can we investigate separation experimentally? • How can numerical models be improved?

Sabine Bonitz

Improved Prediction of Flow Separation for Road Vehicles

<photo of main person (usually PhD

student)>

Time 2013.09 – 2018.08

Customers / partners:

Volvo CC, Volvo GTT, Scania

Funder: FFI

Advisor: Lennart Löfdahl, Alexander Broniewicz

Teddy Hobeika

Reducing aerodynamic drag of road vehicles by cooling airflow control and improved wheel designs Research Motivating Problem: With higher focus on energy efficiency and sustainability in transportation, aerodynamic optimization becomes more and more important as gains in other fields shrink. Wheel designs and thermal management have been an area of focus over the past few years.

Research question: • How does wheel aerodynamics interact with cooling flow?

Deliverables: • Method for simulating tyres in CFD • Method for quantifying cooling flow in wind tunnel tests

Time 2013-05 .. 2017-05

Customers / partners:

Volvo Cars, Volvo Trucks, and Scania

Funder: FFI

Advisor: Lennart Löfdahl, Simone Sebben