Jul 2026· 2026 11th International Conference on Applying New Technology in Green Buildings (ATiGB)· pp. 1023-1028· 0 citations· 15 references
Abstract
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.
In this study, a hot-air-based rotary reactor was designed to address the poor temperature uniformity and low thermal efficiency during tin removal from waste printed circuit boards (WPCBs). Transient computational fluid dynamics simulation was employed to evaluate the effects of fan installation, blade geometry, and the number of shovelling plates on the internal flow and temperature fields in a hot air-based rotary reactor. The optimized combination of a vertical-blade fan and four shoveling plates effectively reduced stagnant zones and maintained the drum-core temperature at around 238 °C. The internal temperature difference in the hot air-based rotary reactor decreased from 17.61 °C to 1.03 °C, and the temperature non-uniformity decreased from 4.16% to 0.22%. Pilot-scale experiments further confirmed the effectiveness of the proposed design. Most of the electronic components were detached after hot air desoldering at 240 °C for 20 min, demonstrating its excellent desoldering performance. The above results might provide a basis for structural optimization and operational guidance of rotary desoldering reactors for WPCBs.
Junjie Zou, Wei Yang· Journal of Physics, Conferen...· 0 citations
Checker bricks in regenerative furnaces gradually accumulate deposits from glass raw materials during long-term operation, reducing heat transfer efficiency and obstructing combustion air and exhaust gas flow. These deposits increase furnace pressure, accelerate checker brick degradation, and shorten furnace service life. This study evaluates the performance of a non-premixed combustion burner for checker brick maintenance. Computational Fluid Dynamics (CFD) simulations were conducted using the non-premixed combustion model in ANSYS Fluent with different air-to-fuel ratios (AFR) and validated experimentally. The optimum performance was achieved at an AFR of 10.6:1, producing a maximum flame temperature of 944°C and a flame length of 1,683 mm, satisfying the required heating temperature and flame penetration for effective deposit removal. Experimental validation showed stable burner operation at air damper openings between 55% and 60%, successfully melting deposits on the checker brick surface. The proposed burner is suitable for regenerative furnace maintenance, while the validated CFD model provides a reliable approach for future burner optimization and heating coverage analysis of checker brick treatment.
Taufik Kurniawan, M. Ikhlas, Mohammad Zaini Ma'ruf· Journal of ocean, mechanical...· 0 citations
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
To address uneven air supply among multiple needle tubes during the drying of high-density forage bales, this study investigated the airflow characteristics and structural optimization of the upper and lower air distribution chambers of a needle-type forage dryer. A three-dimensional CFD model was established, and airflow performance was evaluated using the velocity non-uniformity coefficient M and the inlet-to-outlet total pressure drop Δp. Response surface methodology was used to optimize the key structural parameters. For the upper chamber, installation of a T-shaped baffle and optimization of the cavity height Hc, diffuser angle α, and top-plate opening area ratio Ra yielded an optimal combination of Hc = 133.29 mm, α = 12.51°, and Ra = 1.12, reducing M from 11.2264% to 3.3886%. For the lower chamber, a strip-perforated airflow equalizing plate with Hb = 74.82 mm, D = 23.79 mm, and W = 25.03 mm reduced M from 9.8772% to 1.5484%, with Δp of approximately 130 Pa. Mesh-refinement and turbulence-model sensitivity analyses supported the robustness of the numerical predictions. Repeated outlet-velocity measurements yielded mean absolute relative errors of 3.09%–4.58%. Smoke visualization and grayscale analysis further indicated that the optimized structures enhanced airflow diffusion and redistribution. The results provide guidance for air distribution chamber design in needle-type forage dryers.
X. T. Liu, R. Wang, T. C. Ding· Journal of Applied Fluid Mec...· 0 citations
The performance of briquette drying systems is strongly influenced by airflow distribution and thermal uniformity within the drying chamber, which are governed by outlet configuration and internal flow patterns. However, limited studies have systematically quantified the effect of exhaust outlet arrangements on the coupled heat transfer and fluid flow behavior in industrial-scale briquette ovens. This study aims to numerically investigate the influence of single-, double-, and four-outlet configurations on airflow characteristics, temperature distribution, and overall thermal performance of a briquette drying oven. A three-dimensional geometric model representing the combustion chamber, drying chamber, and briquette racks was developed and analyzed using Computational Fluid Dynamics (CFD). Steady-state simulations were performed in ANSYS Fluent employing the standard k–ε turbulence model, with air properties, inlet velocity (9.97 m/s), and thermal boundary conditions defined based on operational data. The results reveal that outlet configuration significantly affects flow recirculation intensity and temperature uniformity across the briquette racks. The four-outlet configuration produced the most homogeneous airflow distribution and reduced thermal gradients, thereby enhancing convective heat transfer effectiveness compared to single- and double-outlet designs. Conversely, the single-outlet case exhibited pronounced recirculation zones and localized temperature variations, potentially leading to uneven drying. These findings demonstrate that optimizing outlet arrangement is a critical design parameter for improving drying efficiency and energy utilization in briquette oven systems, providing a validated numerical framework for future thermal system optimization.
The convective drying of agricultural materials is an energy-intensive process, and optimizing dryer design is critical for improving efficiency and product quality. This study presents a comprehensive heat and mass transfer model for the convective drying of alfalfa leaves in a rotary drum dryer. Freshly harvested leaves with an initial moisture content of approximately 70% (w.b.) were used as the test material. The proposed system features a simplified drum design aimed at enhancing process efficiency while reducing equipment complexity. The primary objective was to reduce the moisture content of alfalfa leaves to below 50% to ensure their quality during subsequent storage and transportation. To determine the optimal operating conditions, the kinematics of leaf motion inside the rotating drum and the associated heat and mass transfer phenomena were investigated through analytical modeling, numerical simulation, and experimental studies on a laboratory-scale physical model. An analytical model was developed to establish relationships between transverse kinematic characteristics (detachment condition, Froude number, drum inclination angle), average longitudinal velocity, and residence time. Numerical simulations based on the Navier–Stokes equations (continuity, momentum, and energy) provided detailed moisture content distributions within individual leaves under varying airflow orientations and drying durations. The novelty of this work lies in the integrated determination of optimized operating parameters through combined analytical, numerical, and experimental approaches. A regression model relating final moisture content to key process variables (air velocity, temperature of 60 °C, drum rotation frequency and mass of loaded material) was developed from experimental data, yielding practical recommendations for the design and operation of rotary drum dryers for alfalfa and similar agricultural materials.
Gani Zhumatay, O. Zhortuylov, K.A. Moshanov et al.· Applied Sciences· 0 citations