The Arctic region is experiencing accelerated sea ice melt and increased iceberg detachment from glaciers due to climate change.These drifting icebergs present a risk and engineering challenge for subsea installations...The Arctic region is experiencing accelerated sea ice melt and increased iceberg detachment from glaciers due to climate change.These drifting icebergs present a risk and engineering challenge for subsea installations traversing shallow waters,where ice-berg keels may reach the seabed,potentially damaging subsea structures.Consequently,costly and time-intensive iceberg manage-ment operations,such as towing and rerouting,are undertaken to safeguard subsea and offshore infrastructure.This study,therefore,explores the application of extra tree regression(ETR)as a robust solution for estimating iceberg draft,particularly in the preliminary phases of decision-making for iceberg management projects.Nine ETR models were developed using parameters influencing iceberg draft.Subsequent analyses identified the most effective models and significant input variables.Uncertainty analysis revealed that the superior ETR model tended to overestimate iceberg drafts;however,it achieved the highest precision,correlation,and simplicity in estimation.Comparison with decision tree regression,random forest regression,and empirical methods confirmed the superior perfor-mance of ETR in predicting iceberg drafts.展开更多
A computational fluid dynamic （ CFD ） analysis of air movement and aerosol particle transport in a two-zone ventilated room with an inter-zonal opening is presented to study the impact of ventilation strategies and ...A computational fluid dynamic （ CFD ） analysis of air movement and aerosol particle transport in a two-zone ventilated room with an inter-zonal opening is presented to study the impact of ventilation strategies and size of the opening on indoor particle dispersion and concentration distribution. The comparisons of average particle concentrations in both zones between the computations and the experiments from the literature are generally satisfactory and acceptable. The combined effects of sizes of the opening and the inlet and outlet locations （three different strategies） are simulated and discussed. The results show that ventilation strategy and size of the opening influence the particle removal rate in zone 1. The removal rate is decreased when the air supply system is changed from the tap-inlet to the bottom-inlet configuration. The top-inlet system obtains a better particle deposition in zone I than the bottom-inlet configuration. However, the particle concentration at breathing level is lower for bottomsupply system than for top-supply. Decreasing the size of interzonal opening increases the particle deposition rate in zone 1 only for the top.supply system, especially for coarse particles.展开更多
This study investigates the performance of a natural draft dry cooling tower group in crosswind conditions through numerical analysis.A comprehensive three-dimensional model is developed to analyze the steady-state an...This study investigates the performance of a natural draft dry cooling tower group in crosswind conditions through numerical analysis.A comprehensive three-dimensional model is developed to analyze the steady-state and dynamic behavior of the towers.The impact of wind speed and direction on heat rejection capacity and flow patterns is examined.Results indicate that crosswinds negatively affect the overall heat transfer capacity,with higher crosswind speeds leading to decreased heat transfer.Notably,wind direction plays a significant role,particularly at 0°.Moreover,tower response time increases with higher crosswind speeds due to increased turbulence and the formation of vortices.The response times are generally similar for wind directions of 45°and 90°,but differ when facing 0,where the leeward tower exhibits a shorter response time compared to the windward tower.These findings provide valuable insights into the performance of natural draft dry cooling tower groups under crosswind conditions,which can inform the design and operation of similar systems in practical applications.展开更多
Ventilation is one of the factors contributing to energy consumption in buildings and food preservation. The solar chimney proves to be an alternative for reducing conventional energy consumption. Thus, in this study,...Ventilation is one of the factors contributing to energy consumption in buildings and food preservation. The solar chimney proves to be an alternative for reducing conventional energy consumption. Thus, in this study, the performance of a solar chimney with two active faces for thermally drawing air from a chamber for preserving agri-food products was evaluated. These performances were experimentally assessed through data measurements: temperatures and velocities within the chimney, and their analysis using Excel and MATLAB. The obtained results were compared with those from literature to verify their validity. From this study, it is found that the maximum temperature at the chimney outlet reaches 49.4˚C with an average value of 43.7˚C. Additionally, the heating evolution of the chimney air presents four (04) identical phases in pairs, reflecting the chimney’s operation throughout day. The temperature difference between the outlet and inlet of the chimney reaches a maximum of 17˚C with an average of 12.6˚C. Regarding airflow, the maximum air velocity at the chimney outlet is 0.8 m/s, and the average velocities have consistently been greater than or equal to 0.46 m/s. Thus, it can be concluded that the solar chimney is capable of providing ventilation for the preservation chamber through thermal draft.展开更多
文摘The Arctic region is experiencing accelerated sea ice melt and increased iceberg detachment from glaciers due to climate change.These drifting icebergs present a risk and engineering challenge for subsea installations traversing shallow waters,where ice-berg keels may reach the seabed,potentially damaging subsea structures.Consequently,costly and time-intensive iceberg manage-ment operations,such as towing and rerouting,are undertaken to safeguard subsea and offshore infrastructure.This study,therefore,explores the application of extra tree regression(ETR)as a robust solution for estimating iceberg draft,particularly in the preliminary phases of decision-making for iceberg management projects.Nine ETR models were developed using parameters influencing iceberg draft.Subsequent analyses identified the most effective models and significant input variables.Uncertainty analysis revealed that the superior ETR model tended to overestimate iceberg drafts;however,it achieved the highest precision,correlation,and simplicity in estimation.Comparison with decision tree regression,random forest regression,and empirical methods confirmed the superior perfor-mance of ETR in predicting iceberg drafts.
基金National Natural Science Foundation of China (No.40975012)
文摘A computational fluid dynamic （ CFD ） analysis of air movement and aerosol particle transport in a two-zone ventilated room with an inter-zonal opening is presented to study the impact of ventilation strategies and size of the opening on indoor particle dispersion and concentration distribution. The comparisons of average particle concentrations in both zones between the computations and the experiments from the literature are generally satisfactory and acceptable. The combined effects of sizes of the opening and the inlet and outlet locations （three different strategies） are simulated and discussed. The results show that ventilation strategy and size of the opening influence the particle removal rate in zone 1. The removal rate is decreased when the air supply system is changed from the tap-inlet to the bottom-inlet configuration. The top-inlet system obtains a better particle deposition in zone I than the bottom-inlet configuration. However, the particle concentration at breathing level is lower for bottomsupply system than for top-supply. Decreasing the size of interzonal opening increases the particle deposition rate in zone 1 only for the top.supply system, especially for coarse particles.
基金Key Laboratory of Low-Grade Energy Utilization Technologies and Systems(LLEUTS-2023001)the Natural Science Foundation of Chongqing(CSTB2022NSCQ-MSX1470).
文摘This study investigates the performance of a natural draft dry cooling tower group in crosswind conditions through numerical analysis.A comprehensive three-dimensional model is developed to analyze the steady-state and dynamic behavior of the towers.The impact of wind speed and direction on heat rejection capacity and flow patterns is examined.Results indicate that crosswinds negatively affect the overall heat transfer capacity,with higher crosswind speeds leading to decreased heat transfer.Notably,wind direction plays a significant role,particularly at 0°.Moreover,tower response time increases with higher crosswind speeds due to increased turbulence and the formation of vortices.The response times are generally similar for wind directions of 45°and 90°,but differ when facing 0,where the leeward tower exhibits a shorter response time compared to the windward tower.These findings provide valuable insights into the performance of natural draft dry cooling tower groups under crosswind conditions,which can inform the design and operation of similar systems in practical applications.
文摘Ventilation is one of the factors contributing to energy consumption in buildings and food preservation. The solar chimney proves to be an alternative for reducing conventional energy consumption. Thus, in this study, the performance of a solar chimney with two active faces for thermally drawing air from a chamber for preserving agri-food products was evaluated. These performances were experimentally assessed through data measurements: temperatures and velocities within the chimney, and their analysis using Excel and MATLAB. The obtained results were compared with those from literature to verify their validity. From this study, it is found that the maximum temperature at the chimney outlet reaches 49.4˚C with an average value of 43.7˚C. Additionally, the heating evolution of the chimney air presents four (04) identical phases in pairs, reflecting the chimney’s operation throughout day. The temperature difference between the outlet and inlet of the chimney reaches a maximum of 17˚C with an average of 12.6˚C. Regarding airflow, the maximum air velocity at the chimney outlet is 0.8 m/s, and the average velocities have consistently been greater than or equal to 0.46 m/s. Thus, it can be concluded that the solar chimney is capable of providing ventilation for the preservation chamber through thermal draft.
