Computational Aerodynamics and Aeroacoustics of Low-Pressure Axial Fans
Doktorsavhandling, 2025
Electric cooling-fans, or E-fans, play a crucial role in automotive thermal management systems. These fans are typically low-pressure axial fans powered by electric motors. In electric vehicles, cooling-fans generate airflow to reject heat from the coolant circulating through the heat exchanger. These fans are typically operational at low vehicle speeds.
Due to increasingly compact underhood spaces, manufacturers seek greater flexibility in fan placement. As a result, cooling-fans are often placed downstream of other underhood components and consequently ingest spatially non-uniform and turbulent flow. Additionally, to achieve greater flexibility in the placement of cooling-fans, multiple small-diameter fans are often arranged in parallel instead of using a single large-diameter fan. Furthermore, in electric vehicles, the absence of masking noise from the internal combustion engine makes the noise produced by cooling-fans more significant.
Both rotor blade geometry and inflow conditions—which depend on fan installation—influence turbomachines' aerodynamic performance and noise. This work examines the effects of rotor blade design and installation on the aerodynamic and aeroacoustic performance of low-pressure axial fans using Computational Fluid Dynamics (CFD) and Computational Aeroacoustics (CAA).
Four rotor blade designs with varying blade-loading-distributions are generated using the Blade Element Momentum (BEM) method for low-solidity blades. Their aerodynamic performance is evaluated under both uniform and non-uniform inlet flow conditions, using a generic non-uniform profile. The aeroacoustic performance is evaluated numerically only under uniform inflow conditions.
Installation effects are studied through four numerical investigations, analyzing the aerodynamic and aeroacoustic impacts of an upstream blockage, parallel operation of two low-pressure axial fans, and reduced inlet bellmouth dimensions. Ultimately, this study summarizes the design process for low-pressure axial fans and typical installation effects.
Due to increasingly compact underhood spaces, manufacturers seek greater flexibility in fan placement. As a result, cooling-fans are often placed downstream of other underhood components and consequently ingest spatially non-uniform and turbulent flow. Additionally, to achieve greater flexibility in the placement of cooling-fans, multiple small-diameter fans are often arranged in parallel instead of using a single large-diameter fan. Furthermore, in electric vehicles, the absence of masking noise from the internal combustion engine makes the noise produced by cooling-fans more significant.
Both rotor blade geometry and inflow conditions—which depend on fan installation—influence turbomachines' aerodynamic performance and noise. This work examines the effects of rotor blade design and installation on the aerodynamic and aeroacoustic performance of low-pressure axial fans using Computational Fluid Dynamics (CFD) and Computational Aeroacoustics (CAA).
Four rotor blade designs with varying blade-loading-distributions are generated using the Blade Element Momentum (BEM) method for low-solidity blades. Their aerodynamic performance is evaluated under both uniform and non-uniform inlet flow conditions, using a generic non-uniform profile. The aeroacoustic performance is evaluated numerically only under uniform inflow conditions.
Installation effects are studied through four numerical investigations, analyzing the aerodynamic and aeroacoustic impacts of an upstream blockage, parallel operation of two low-pressure axial fans, and reduced inlet bellmouth dimensions. Ultimately, this study summarizes the design process for low-pressure axial fans and typical installation effects.
upstream blockage
fans in parallel
CAA
blade design
cooling-fans
CFD
low-pressure axial fans
Lecture Room, HC3
Opponent: Prof. Stephane Moreau, University of Sherbrooke, Canada
Författare
Debarshee Ghosh
Chalmers, Mekanik och maritima vetenskaper, Strömningslära
Computational Fluid Dynamics Simulations of Aerodynamic Performance of Low-Pressure Axial Fans with Upstream Blockage
SAE Technical Papers,;(2024)
Paper i proceeding
Aerodynamic Analysis of Low-Pressure Axial Fans Installed in Parallel
Journal of Fluids Engineering, Transactions of the ASME,;Vol. 146(2024)
Artikel i vetenskaplig tidskrift
Computational aeroacoustics of low-pressure axial fans installed in parallel
Journal of Fluids Engineering, Transactions of the ASME,;Vol. 147(2024)
Artikel i vetenskaplig tidskrift
Computational Aeroacoustics of Inlet Geometry on Tip Noise for Low Pressure Axial Fans
AIAA SciTech Forum and Exposition, 2024,;(2025)
Paper i proceeding
Evaluation of hybrid computational aeroacoustic methods applied to automotive cooling-fans, Ghosh, D., Vourakis, M., Boström, A., Andersson, N., Roy, A., Etemad, S
Aerodynamic and Aeroacoustic Effect of Blade Loading Distribution For Low-Pressure Axial Fans, Ghosh, D., Andersson, N., and Etemad, S.
Electric cooling-fans, or E-fans, play a crucial role in automotive thermal management systems. These fans are typically low-pressure axial fans powered by electric motors. In electric vehicles, cooling-fans generate airflow to reject heat from the coolant circulating through the heat exchanger and are typically operational at low vehicle speeds. Due to increasingly compact underhood spaces, manufacturers seek greater flexibility in fan placement. As a result, cooling-fans are often placed downstream of other underhood components and consequently ingest spatially non-uniform and turbulent flow. Additionally, to achieve greater flexibility in the placement of cooling-fans, multiple small-diameter fans are often arranged in parallel instead of using a single large-diameter fan. Furthermore, in electric vehicles, the absence of masking noise from the internal combustion engine makes the noise produced by cooling-fans more significant. Therefore, for electric vehicles both the aerodynamic and acoustic performance of the cooling-fan is of significance, in particular at low vehicle speeds.
The current generation of cooling-fans are typically designed and tested under ideal, clean inlet flow conditions on test rigs, free from spatial or temporal disturbances. Additionally, in most current automotive cooling solutions, multiple low-pressure axial fans are placed in parallel instead of using a single large-diameter fan. To address these concerns, this research work aims to extend the previous work done with regard to the effect of ingesting spatially non-uniform flow, to fans representative of those used in automotive cooling systems through Computational Fluid Dynamics (CFD) and Computational Aeroacoustics (CAA) investigations. Consequently, also evaluate the suitability of a variety of numerical methods of different fidelity to accurately capture the effect of installation effects by comparing numerical data to publicly available experimental data. Additionally, this research work also aims to numerically investigate the aerodynamic and acoustic effect of placing low-pressure axial fans in parallel.
The current generation of cooling-fans are typically designed and tested under ideal, clean inlet flow conditions on test rigs, free from spatial or temporal disturbances. Additionally, in most current automotive cooling solutions, multiple low-pressure axial fans are placed in parallel instead of using a single large-diameter fan. To address these concerns, this research work aims to extend the previous work done with regard to the effect of ingesting spatially non-uniform flow, to fans representative of those used in automotive cooling systems through Computational Fluid Dynamics (CFD) and Computational Aeroacoustics (CAA) investigations. Consequently, also evaluate the suitability of a variety of numerical methods of different fidelity to accurately capture the effect of installation effects by comparing numerical data to publicly available experimental data. Additionally, this research work also aims to numerically investigate the aerodynamic and acoustic effect of placing low-pressure axial fans in parallel.
Ämneskategorier (SSIF 2025)
Strömningsmekanik
Annan maskinteknik
Maskinteknik
Farkost och rymdteknik
Teknisk mekanik
ISBN
978-91-8103-169-0
Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 5627
Utgivare
Chalmers