The study of energy savings in ventilation systems within buildings is crucial. Impinging jet ventilation (IJV) systems have garnered significant interest from researchers. The identification of the appropriate location for the IJV reveals a gap in the existing literature. This research was conducted to address the existing gap by examining the impact of IJV location on energy savings and thermal comfort. A comprehensive three-dimensional CFD model is examined to accurately simulate the real environment of an office room (3 × 3 × 2.9 m3) during cooling mode, without the application of symmetrical plans. Four locations have been selected: two at the corners and two along the midwalls, designated for fixed-person positions. The return vent height is analyzed utilizing seven measurements: 2.9, 2.6, 2.3, 1.7, 1.1, 0.8, and 0.5 m. The RNG k–ε turbulence model is implemented alongside enhanced wall treatment. The findings indicated that the optimal range for the return vent height is between 1.7 and 0.8 m. It is advisable to utilize the IJV midwall 1 location, positioned behind the seated individual and away from the exterior hot wall. It is characterized by low vortex formation in the local working zone that contributes to a more comfortable sensation while providing recognized energy-saving potential.
14 July 2020 in Arabian Journal for Science and Engineering
This study focuses on the aerodynamic optimization of the re-entry capsule (REC) Orion Crew Exploration Vehicle (CEV) module, evaluating its performance using computational fluid dynamics (CFD). Three different models, namely Baseline, 2-Duct, and 4-Duct, are investigated under a wide range of flow speeds, from supersonic (Ma=1.6) to hypersonic (Ma=6) regimes. Thermofluids aspects, drag coefficient, surface heat flux, and the effectiveness of the modified geometry are assessed using aerodynamic and temperature-based models. The results show that the introduction of ducts in the 2-Duct and 4-Duct models leads to an average decrease in the drag coefficient of approximately 2.1% and 2.9%, respectively, compared to the baseline model, across all Mach numbers. The maximum reduction in drag coefficient is 3.55%, observed at Ma=1.4 using the 4-Duct capsule. However, it is found that the addition of extra ducts to the model increases the maximum heat transfer rate. Specifically, the heat flux is increased by up to 69% for the 4-Duct model at Ma=6, compared to the baseline model. On average, the heat flux is increased by approximately 28.6% for all conditions. The findings indicate that the introduction of ducts in the REC model improves its aerothermodynamic performance by reducing drag but also increases the heat transfer rate on the surface.