| 1. |
- Arora, Sampann, et al.
(author)
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A partitioned FSI methodology for analysis of sloshing-induced loads on a fuel tank structure
- 2020
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In: Proceedings of the 6th European Conference on Computational Mechanics: Solids, Structures and Coupled Problems, ECCM 2018 and 7th European Conference on Computational Fluid Dynamics, ECFD 2018. ; , s. 3037-3048
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Conference paper (peer-reviewed)abstract
- Liquid sloshing is a source of major concern in the structural design of containers. In fuel tanks of heavy duty trucks, with capacities of up to 900 litres, this phenomenon is capable of causing fuel to impact the container tank with high forces, and exposing the vulnerable parts of the tank to heavy dynamic loads. This highly non-linear and transient phenomenon is simulated here using the commercial Computational Fluid Dynamics (CFD) code STAR-CCM+. The two phase problem is solved using the VOF interface capturing approach. Owing to the thin walled structures of the fuel tank, it becomes important to account for the effects of Fluid-Structure Interaction (FSI). To this end, a partitioned FSI methodology is employed by coupling the CFD and Finite Element Analysis (FEA) solvers for this multi-physics problem. One-way and two-way coupled FSI methodologies are compared with experimental results. The one-way coupled simulations yield good agreement of wall deformations with the experiments for low filling levels. While the two-way coupled FSI analysis corroborates well with the experiments for all filling levels, its high computational costs render the one-way coupled methodology a promising tool to analyse sloshing for industrial applications. This coupling strategy could inform a fuel tank design suited to prevent structural damage due to sloshing, thus contributing towards its safety and longevity.
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| 2. |
- Ghosh, Debarshee, 1995, et al.
(author)
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Aerodynamic Analysis of Low-Pressure Axial Fans Installed in Parallel
- 2024
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In: Journal of Fluids Engineering, Transactions of the ASME. - 1528-901X .- 0098-2202. ; 146:5
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Journal article (peer-reviewed)abstract
- Ducted rotor-only low-pressure axial fans play an integral role in automotive thermal management. The tightly packed under-hood region and down-stream heat-exchanger shape limit the fan diameter. In order to circumvent this limitation, multiple cooling fans of small diameters are tightly packaged and placed in parallel. Currently, there is limited scientific work, that study the aerodynamics of low-pressure axial fans when installed in parallel. This work aims to quantify the aerodynamic performance and the flow-field as a result of installing low-pressure axial fans in parallel through computational fluid dynamics (CFD). Publicly available experimental data from Friedrich-Alexander University is used for the validation of the numerical setup. Three-dimensional, full-annulus, unsteady Reynolds-averaged Navier‐Stokes (URANS) analysis has been performed for both a single-fan and two-fans installed in parallel and their respective aerodynamic performance has been compared for the operation condition identified as the best efficiency point in experiments. Only small differences are observed in the overall aerodynamic performance of the two-fans in parallel compared to a single-fan. A circumferential nonuniformity in the form of a local high-pressure zone at the inlet of the fan is observed when the two-fans are placed in parallel. The resulting circumferential nonuniformity is quantified, both in space and time. A strong correlation is found between the pressure fields of the two-fans installed in parallel.
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| 3. |
- Ghosh, Debarshee, 1995, et al.
(author)
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Computational Fluid Dynamics Simulations of Aerodynamic Performance of Low-Pressure Axial Fans with Upstream Blockage
- 2024
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In: SAE Technical Papers. - 0148-7191 .- 2688-3627.
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Conference paper (peer-reviewed)abstract
- Rotor-only ducted low-pressure axial fans play a crucial role in automotive thermal management of the tightly packed under-hood region. Most current scientific work concerning low-pressure axial fans investigate the aerodynamic performance of these fans while operating with uniform inlet flow conditions. This is rarely the case in real-world applications. This work aims to investigate the aerodynamic performance of low-pressure axial fans operating with upstream blockages. First, a validation study is performed in the absence of any upstream blockage. Numerical results are compared against publicly available experimental data. Steady-state, Reynolds-Averaged Navier Stokes (RANS) analysis is performed on a single-blade passage. The validation study also evaluates the choice of turbulence model and suggests the use of the k- ε turbulence model with wall functions for the best comparison against experimental data. To study the effect of upstream blockage, a generic blockage disc is positioned upstream of the fan inlet. Three different radial extents of the blockage disc is evaluated, such that different radial extents of the blade span is blocked. A strong influence of the upstream blockage is observed on the fan performance and flow distribution along the blade span. The total-to-static pressure coefficient and the total-to-static efficiency decrease proportionately to the extent of blockage in the radial direction. The peak total-to-static efficiency moves to a lower flow coefficient with increase in upstream flow blockage. This is deemed undesirable for automotive applications where it is desirable to have maximum aerodynamic efficiency at the highest possible flow coefficient.
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| 4. |
- Ramesh Babu, Anandh, 1996, et al.
(author)
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An adaptive cabin air recirculation strategy for an electric truck using a coupled CFD-thermoregulation approach
- 2024
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In: International Journal of Heat and Mass Transfer. - 0017-9310. ; 221
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Journal article (peer-reviewed)abstract
- Cabin climatization is one of the largest auxiliary loads in an electric vehicle, and its performance significantly affects the driving range. Recirculating climatized air from the cabin has been shown to reduce energy consumption, but at the risk of fogging the windows and deteriorating the air quality. Therefore, many automobile manufacturers refrain from adopting it at low ambient temperatures. In this paper, an adaptive recirculation strategy that takes these issues into account is proposed and studied on an electric truck cabin while heating. Numerical simulations were performed using a coupled CFD-thermoregulation model, with the consideration of humidity and CO2. The JOS-3 thermoregulation model was employed for estimations of skin temperatures and evaporation of vapor from the skin, and the Berkeley comfort model was used to evaluate the comfort metrics. Ten scenarios were considered at various vehicle speeds, temperatures, and relative humidity levels while evaluating them with and without the proposed return-air strategy. The controller adapted between humidity and CO2-critical conditions during run-time. The fresh-air mass flow requirements reduced with increasing difference between the setpoint and ambient vapor mass fractions under humidity critical conditions, and plateaued at 10 g/s where CO2 was more critical. The proposed strategy provided energy savings ranging from 9% to 34% depending on the operating condition.
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| 5. |
- Vasudevan, Sudharsan, 1991, et al.
(author)
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Comparative analysis of single and multiphase numerical frameworks for subcooled boiling flow in an internal combustion engine coolant jacket
- 2023
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In: Applied Thermal Engineering. - : Elsevier BV. - 1359-4311. ; 219
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Journal article (peer-reviewed)abstract
- Computational analysis of nucleate boiling occurring in liquid cooled applications, such as internal combustion engines is often implemented within a single phase Computational Fluid Dynamics (CFD) framework, owing to low vapor fractions involved. With increase in specific power and the resulting higher thermal loads, accounting for the presence of the vapor phase using a multiphase framework is required in certain conditions, despite the higher computational costs. While detailed resolution of the liquid and vapor phases in nucleate boiling using a two fluid model is excessively computationally expensive, the homogeneous mixture multiphase framework is a good compromise between resolution and computational cost. In this article a numerical wall boiling model is implemented within both, a single phase and the mixture multiphase frameworks. Results from the two approaches are compared with measurements in a channel flow. The results from both approaches are in good agreement with experiments. The single phase approximation is valid when the vapor generation is low. The sensitivity of the results to the computational grid is also discussed in detail. Further, the two frameworks are used to simulate the heat transfer in the coolant jacket of a four-cylinder petrol engine. The results from the numerical simulations are compared with measurements. Both computational frameworks compare reasonably well with the measurements in terms of local metal temperature. However, the advantage of accounting for the vapor phase using the mixture multiphase framework is evident when the parameter related to vapor bubble interactions is analyzed in detail.
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