Numerical Analysis of Outlet Number Effects on Temperature Distribution in a Briquette Oven Using CFD

Two-Phase Flow Distribution in Plate Heat Exchangers Using a Coupled CFD–Distributed Parameter Model

Plate heat exchangers (PHEs) play a critical role in the energy efficiency of heat pump systems. However, non-uniform two-phase flow distribution across parallel channels remains a key limitation, as it may cause local dryout and degrade heat transfer performance. To address the limitations of existing prediction approaches, a hybrid modeling framework coupling computational fluid dynamics (CFD) simulations with a distributed parameter model is developed. The model is validated against experimental data under 12 representative operating conditions. The results show that the average prediction errors for the total mass flow rate, pressure drop, and heat transfer rate are within 3%, ±10%, and ±5%, respectively. The influences of refrigerant outlet conditions and inlet distributor geometry on flow distribution uniformity are systematically investigated, identifying the dominant factors governing pressure drop and the mechanism by which distributor orientation improves uniformity. Quantitative optimization shows that an orifice orientation of 225° reduces flow non-uniformity by 67.8% and enhances the heat transfer rate by 4.33% compared with the distributor-free design. The proposed method is robust across various operating scenarios and provides a reliable, quantitative tool for optimizing PHE inlet distributor designs.

Numerical Investigation of Airflow Temperature and Velocity Distribution in a Cleanroom

Optimization Analysis of Thermal Distribution in a Confined Balcony Space Under Air-Conditioning Outdoor Unit Operation Using Taguchi-Based CFD Simulation

This study analyzes the thermal behavior and airflow characteristics within a confined balcony space under typical hot and humid climatic conditions in Ho Chi Minh City. A computational fluid dynamics (CFD) model was developed and numerically assessed through mesh-independence and convergence analyses, incorporating an external air domain to ensure realistic boundary conditions. The Taguchi method, combined with analysis of variance (ANOVA), was employed to evaluate the influence of four key factors: number of outdoor units, installation position, ventilation opening ratio, and ambient wind velocity. The results indicate that the number of outdoor units is the dominant factor affecting the average balcony temperature, contributing the largest variation. Ambient wind velocity has a moderate influence, while installation position and ventilation opening ratio exhibit relatively minor effects. The consistency between Taguchi and ANOVA analyses confirms the reliability of the findings. Based on the signal-to-noise (S/N) ratio analysis using the “smaller-thebetter” criterion, the optimal configuration was identified as A1-B2-C1-D1. A verification simulation showed that the model converged and achieved an average temperature of 304.24 K, significantly lower than in the initial simulation cases. The findings highlight the importance of controlling internal heat sources and optimizing airflow pathways to improve thermal conditions in confined balcony spaces. This study provides practical insights into the design and installation of airconditioning systems in urban residential buildings.

CFD analysis of heat and flow in coach bus with different vents: the effect of size and position

Influence of Structural Parameters on Airflow Uniformity and Optimisation of a Tower-type Air-assisted Sprayer Based on Computational Fluid Dynamics

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.

Computational Fluid Dynamics-Based Characterization of Heat Transfer and Airflow in an Indirect Solar Fish Dryer Under Tropical Conditions

Indirect solar drying is a widely adopted fish preservation technique in tropical regions, valued for its low energy requirement and capacity to enhance product quality. However, non-uniform airflow and temperature distribution within drying chambers remain persistent design challenges that compromise drying efficiency and product consistency. This study investigated the airflow characteristics and convective heat transfer performance of an indirect solar fish dryer through computational fluid dynamics (CFD) simulation and experimental validation. A three-dimensional CFD model was developed to simulate temperature distribution and airflow patterns under forced convection, with an inlet air velocity of 1.2 m·s⁻¹ and an inlet air temperature of 60 °C. Experimental air temperatures were recorded inside the drying chamber during actual drying operations and compared with simulated values using linear regression and root-mean-square error (RMSE). The regression analysis yielded a strong linear relationship between simulated and experimental temperatures (R² = 0.9413), with an RMSE of 3.41 °C, indicating reasonable agreement in absolute temperature prediction. These results confirm that the CFD model accurately represents the thermal behavior and convective heat transfer characteristics of the dryer. The validated CFD framework provides a reliable, cost-effective tool for evaluating and optimizing the design and operational performance of indirect solar fish dryers under tropical conditions, thereby reducing reliance on iterative physical prototyping.