Jul 2026· International Journal of Automotive Science and Technology· Vol 10, pp. 501-507· 0 citations· 13 references
Abstract
Internal combustion engines require efficient air intake systems to optimize combustion and reduce emissions. The intake manifold plays a critical role in distributing the fresh air or air fuel mixture to each cylinder equally. Any imbalance leads to reduced volumetric efficiency and increased vibration. This study investigates the original intake manifold design of a four cylinder Toyota 4A-FE engine to address flow distribution issues. The primary objective is to evaluate the influence of geometric parameters on the aerodynamic performance of the manifold. To achieve this, a three dimensional model of the manifold was created using SolidWorks software. Numerical simulations were performed using ANSYS Fluent software with the standard k-ω SST turbulence model to capture the flow characteristics accurately. A parametric study was conducted by modifying the angles of the runners relative to the base floor at 36°, 37°, 39°, 41°, 43° and 45°, alongside varying the outlet widths between 40 mm and 50 mm. The computational results provided detailed insights into pressure distribution, velocity profiles, and mass flow rates across the four cylinders. By comparing the original manifold with the modified designs, the study identified the specific configuration that yields the most balanced cylinder to cylinder air distribution. The findings demonstrate that the optimal configuration, featuring a 45° runner angle and a 42.5 mm outlet width, significantly reduces flow imbalances. Specifically, this optimized design decreased the maximum velocity deviation among the cylinders by 62% and narrowed the mass flow rate distribution deviation by 40%, thereby promoting a highly uniform velocity field. This research provides a valuable structural framework for enhancing the performance of naturally aspirated engines through targeted manifold design modifications.
This research presents a detailed computational assessment of a shell-and-tube heat exchanger equipped with helical baffles, emphasizing the
influence of baffle pitch on the system’s overall thermal and hydraulic behavior. The primary aim was to enhance heat transfer capability while
limiting pressure losses, which is an essential requirement for industrial sectors such as energy production, petrochemicals, refrigeration, and
HVAC (Heating, Ventilation, and Air Conditioning) applications. The heat exchanger model was constructed in CATIA V5, and CFD (Computational
Fluid Dynamics) simulations were performed in ANSYS Fluent 15.0 to analyze the impact of different baffle pitches (ranging from
26 to 50 mm) on shell-side performance parameters: pressure drop, temperature difference, and total heat transfer rate over a mass flow range
between 0.1571 and 0.6284 kg/s. The computational results found a 38-mm baffle pitch as the most efficient configuration, yielding a maximum
heat transfer rate of 14.9 kW and a temperature reduction of 8.4 °C, with a moderate pressure penalty. Visualization of the flow field confirmed
the formation of stable swirling and crossflow zones that promote effective mixing without introducing excessive resistance. The study delivers
a systematic CFD-based analysis covering a broad range of operating conditions and offers practical guidelines for perfecting industrial heat
exchanger designs. The novelty of this work lies in its quantitative evaluation strategy, which decides the best configuration through balanced
consideration of both thermal enhancement and fluid dynamic efficiency. In addition to conventional thermal and hydraulic parameters, the
study introduces a thermal–hydraulic performance metric based on the heat transfer rate per unit pressure drop(Q/ΔP). This index provides
an integrated measure of heat transfer effectiveness compared to pumping power. Analysis of this performance index further confirms that the
38 mm pitch delivers the highest thermal–hydraulic efficiency, confirming it as the best configuration across all tested operating conditions.
D. M. Yadav, M. Basha, Dr. B. Omprakash et al.· Journal of Thermal Engineeri...· 0 citations
Pressure losses in heating, ventilation, and air-conditioning (HVAC) duct elbows significantly increase fan power requirements and reduce overall system efficiency. This study presents a comprehensive computational fluid dynamics (CFD) investigation aimed at identifying effective strategies for reducing pressure losses in 90° HVAC duct elbows. The numerical methodology was first validated against published experimental measurements, demonstrating excellent agreement and providing confidence in the predictive capability of the CFD model. The validated model was then employed to evaluate the influence of duct geometry, inlet velocity, guide vane configuration, inter-vane spacing, perforated guide vanes, and duct material roughness on aerodynamic performance using the SST k–ω turbulence model. The results show that round elbows reduce pressure losses by approximately 50% compared with hydraulically equivalent rectangular elbows, highlighting the strong influence of duct geometry on flow separation. Among the flow-control strategies investigated, curved guide vanes produced the greatest improvement, with an optimized three-vane arrangement and a non-dimensional spacing of s/Dh≈0.15 (corresponding to 150 mm for the specific geometry tested) reducing pressure losses by approximately 31% relative to the baseline elbow without guide vanes. In contrast, the investigated perforated guide vane provided only marginal improvement, indicating that its geometry requires further optimization to minimize blockage and mixing losses. The material roughness study showed that smooth, rigid duct materials produced only minor differences in pressure loss, whereas flexible ducts generated noticeably higher losses because of their increased surface roughness. These findings demonstrate that optimizing elbow geometry and guide vane design is considerably more effective than modifying duct material or using the investigated perforated vane configuration. The study provides practical design recommendations for improving the aerodynamic performance and energy efficiency of HVAC duct systems.
M. Fouad, Mostafa Rizk, Anoud Nagaf et al.· Machines· 0 citations
This study evaluates the impact of hot air inlet positioning on heat transfer efficiency within a biomass-fueled rotary drum dryer system using Computational Fluid Dynamics (CFD) simulation combined with experimental validation. Three inlet configurations - at the drum head, at one-third of the drum length, and at the center of the drum - were compared based on velocity distribution, temperature fields, and energy loss characteristics. Simulation results using ANSYS Fluent indicate that the head-inlet configuration leads to non-uniform thermal distribution and high exhaust velocities $(\approx 3 mathrm{m} / \mathrm{s})$. Conversely, the internal-inlet configuration optimizes airflow circulation with lower velocities $(\approx \mathbf{1} \mathrm{m} / \mathrm{s})$, enhancing heat transfer efficiency to the material bed and minimizing energy loss to the environment. Experimental drying of agricultural products within a temperature range of 60-80°C confirmed the accuracy of the simulation model, with deviations in final temperature and moisture content below 5%. The results demonstrate that the internal-inlet configuration shortens drying time and improves product uniformity. This research confirms the critical role of CFD simulation in designing and optimizing renewable energy drying systems, particularly for decentralized small-scale production.
Phu Nguu Do, M. Nguyen, Tan Trung Ho· 2026 11th International Conf...· 0 citations
Improving the performance of radial inflow turbines under coupled aerodynamic and mechanical constraints remains a key challenge in high-speed Organic Rankine Cycle (ORC) systems. In magnetically supported configurations, turbine design is restricted by axial thrust limitations, while maintaining the target mass flow rate is essential for stable system operation. To address these challenges, this study develops a physics-guided design approach for a high-speed ORC radial inflow turbine by integrating one-dimensional preliminary design, three-dimensional CFD-based optimization, and enthalpy gradient magnitude (EGM)-based flow diagnostics. The numerical model is validated against experimental data of a baseline turbine. Three key geometric parameters are optimized under coupled axial thrust and mass flow constraints. The optimized design increases the total-to-total isentropic efficiency from 74.7% to 87.1% while maintaining acceptable axial loading. EGM analysis shows that high-efficiency configurations exhibit more uniform spatial distributions of energy gradients within the impeller passages, whereas low-efficiency cases are characterized by localized high-gradient regions associated with flow separation and secondary flow structures. A volumetric average EGM parameter is further introduced for quantitative evaluation and exhibits a clear negative correlation with turbine efficiency. The optimized efficiency reported herein is a numerical prediction requiring future experimental validation. The results demonstrate that improved internal flow organization contributes significantly to turbine performance enhancement and provides diagnostic insights for design evaluation of high-speed ORC turbines.
Bochen Wan, Wang Zheng, Yueyang Wang et al.· Energies· 0 citations
In air-assisted orchard spraying, airflow characteristics strongly determine spray performance. This study designed a tower-shaped fan for grape canopies and investigated its aerodynamic behaviour. A three-dimensional computational fluid dynamics (CFD) model of the internal flow field was established to quantify the effects of shroud taper, upper and lower guide-vane angles, inlet diameter, and inlet position on outlet air-velocity uniformity. Single-factor simulations confirmed that all selected structural parameters significantly affect the outlet air velocity’s coefficient of variation (CV). Based on these results, central composite design was applied for multi-parameter optimisation. A second-order regression model was developed to describe the relationship between guide-vane angles, shroud taper, inlet position, inlet diameter, and air-velocity CV response. Analysis of variance showed that the influence of the factors decreased in the following order: guide-vane angle > inlet position > inlet diameter > shroud taper. Numerical optimisation identified the optimal configuration as a guide-vane angle of 118.37°, shroud taper of 23.84°, inlet position of 29.35 mm, and inlet diameter of 493.92 mm. Under these conditions, the predicted air-velocity CV decreased to 12.07%. A field validation experiment was conducted using representative measurement points selected from the simulated velocity distribution. The maximum relative error between measured and simulated values was below 6%, indicating strong agreement. These results confirm the reliability of the CFD model and demonstrate its effectiveness for structural optimisation of orchard air-assisted spraying equipment.
P. Zhan, Z. Y. Sun, Q. Meng et al.· Journal of Applied Fluid Mec...· 0 citations
Reducing aerodynamic drag on medium-duty freight trucks is essential for improving fuel efficiency; however, the relationship between local flow modification, aerodynamic loads, and propulsion-power demand has not yet been sufficiently quantified. This study evaluates the aerodynamic influence of a front deflector on a Chevrolet NQR 1015 box truck using steady RANS CFD with the k–ω SST turbulence model under zero-yaw conditions from 50 to 120 km/h. The numerical setup included near-wall inflation layers and mesh characterization, as well as grid-independence assessments based on CD, and the Grid Convergence Index. The deflector produced consistent aerodynamic improvements, reducing average drag coefficient by 14.1%, while the average lift coefficient decreased by 73.5%. These aerodynamic changes reduced the average required propulsion power from 53.86 kW to 50.39 kW, corresponding to a 6.4% reduction, with a maximum saving of 8.1% at 120 km/h. Pressure, velocity, and pressure-coefficient CP distributions indicate that the deflector promotes smoother flow redirection at the cab–box transition, attenuates suction peaks, and suggests lower pressure losses associated with the separated-flow and wake regions.
Víctor Geovanni Suntaxi Suntaxi, Alexis Cordovés García, R. L. Avila Rondón· Vehicles· 0 citations