Inlet Air Flow Rate Research Articles

Comparative Analysis of Heat Transfer Coefficient Using Experimental Data and Empirical Expressions

This study aims to determine the heat transfer coefficient by comparing results obtained from both experimental methods and empirical expressions. A controlled experiment involving the flow of water through a polyethylene hose was conducted, and the heat transfer coefficient was calculated based on inlet and outlet temperatures. These findings were then compared with values derived from empirical correlations, specifically the Sieder-Tate equation, to assess accuracy and reliability. The experimental setup maintained consistent boundary conditions, including water inlet temperature, airflow rate, and hose orientation. The results indicated that the experimentally determined heat transfer coefficient was 48.30 W/(m²·K), while the empirical calculation yielded a value of 53.44 W/(m²·K). The slight discrepancy between these values highlights minor experimental errors and assumptions inherent in empirical models. Overall, the close agreement between the experimental and empirical values validates the use of empirical correlations for predicting heat transfer coefficients in similar configurations. This study provides valuable insights for optimizing heat transfer processes in various industrial and engineering applications, emphasizing the importance of experimental validation. Future work could explore extended parameter ranges, advanced measurement techniques, and numerical simulations to further enhance the accuracy and applicability of the findings.

Comprehensive numerical and experimental analysis the impact of employing vortex generators on evaporative cooling process

Reduced energy usage is an important concern in vapor compression cooling systems, particularly in hot climates. These systems function poorly in hot weather and consume a lot of electricity. Evaporative condensers use the cooling impact of evaporation to facilitate the process of heat rejection and thereby increase energy efficiency. This work evaluates the impact of employing vortex generators on the performance of an evaporative condenser. The analysis is performed using a validated numerical model, a commercial CFD code. The proposed vortex generators are parallel plates with sinusoidal and zigzag patterns. Dry air enters a channel equipped with four vortex-generating plates and water spray. The incoming dry air cools due to the two-phase heat transfer during air contact with the sprayed water droplets, and the cooled air with the proper humidity level exits the channel. The investigated parameters include longitudinal nozzle position, inlet air flow rate, pitch, and the height of the vortex generator plates in two sinusoidal and zigzag modes and the obtained results are compared with the plain channel model. Greater inlet air velocity resulted in superior output temperatures and pressure drops, yet lower outlet relative humidity and water mass percentage. According to the findings, the air pressure drop and outlet dry temperature are raised by 152 % and 5 %, respectively, when the incoming air velocity is altered from 0.4 to 0.6 m. s−1 (50 % growth), and the nozzle position is moved from X = 1.35 m to X = 1.85 m (37.04 % change) from the channel entrance, while the relative humidity and water mass fraction are decreased by 19 % and 11 %, respectively. Additional research revealed that the vortex flow level is lower when the nozzle is positioned farther away from the plates, and the water spray's impact on lowering the local air temperature in vortex-flowing areas is more substantial when it is positioned closer to the plates. Furthermore, increasing wave height and pitch values of vortex generators result in a more extensive air pressure drop in the channel, and vice versa. This means that, at a fixed pitch, a higher plate wave height raises the amount of vortex flows. According to the findings, sinusoidal vortex plates have better efficiency than the zigzag ones, and in a channel equipped with water spray, the use of vortex plates before the water spray nozzles lowers the dry temperature at the outlet by about one °C compared to that of the plain channel.

Experimental study on the vacuum dehumidification performance of PVA/CaCl2 selective permeation membrane under vortex conditions

Vacuum membrane dehumidification is a promising power-saving isothermal dehumidification technology, and the development of low-cost and efficient selective permeation membranes is beneficial to its application. In this study, the dehumidification performance and mechanism of the PVA/CaCl2 water vapor selective permeation membrane are investigated experimentally. The effects of the CaCl2 concentration in the casting membrane solution, the permeation side vacuum level, and the inlet air flow rate and relative humidity on the dehumidification performance are discussed. In addition, the effect of the deflector fins on the dehumidification performance is analyzed. The results show that the vortex coupled dissolution-diffusion theory can explain the experimental results. In addition, from the point of view of dehumidification capacity per unit power consumption, the best concentration of CaCl2 in casting membrane solution is 2.08 %, and the worst permeation side vacuum level is 60 kPa. The higher the inlet air flow rate and relative humidity under the deflector fins, the better the dehumidification performance. The dehumidification performance can be significantly improved by the deflector fins, which increase the COP by 38.31 %∼146 % and the selectivity by 35.85 %∼147 %.

Performance assessment of packed bed systems for humidity control in greenhouse applications: An experimental based AI modelling approach

Optimal humidity control is essential for enhancing crop yields and ensuring favourable growth conditions in greenhouse agriculture. Packed bed devices are effective tools for regulating humidity levels; however, accurately assessing their performance, especially for temperate oceanic climates, is yet explicitly unexplored. The current paper presents a packed bed system using water as the working fluid to increase humidity during winter for greenhouse cultivation. An experimental setup is developed, and a detailed parametric study is conducted. Also, an artificial intelligence (AI) based multi-layer perceptron neural network (MLPNN) is designed to evaluate the performance of packed bed systems under varying environmental conditions with different inlet air flow rates (176 m³/hr, 286 m³/hr, 383 m³/hr, and 428 m³/hr). The results show that the system achieves a significant 50% increase in humidity ratio, transitioning from an inlet humidity ratio of 6 g/kgda to an outlet ratio of 9 g/kgda when operating with water at an average temperature of 15.7°C and a flow rate of 12.8 kg/min. The MLPNN is trained with 112 non-repeated datasets and observed that a topology of 2-10-10-1 includes 2 input neurons, 2 hidden layers with 10 neurons each, and 1 output neuron, has high prediction accuracy in estimating Δωa values for the packed bed system. The predictions closely align with experimental data, showing a maximum discrepancy within ±2.5%. This research advances the use of packed bed systems by providing a comprehensive framework for assessing and improving humidity control in greenhouse environments.

Performance assessment of packed bed systems for humidity control in greenhouse applications: An experimental based AI modelling approach

Optimal humidity control is essential for enhancing crop yields and ensuring favourable growth conditions in greenhouse agriculture. Packed bed devices are effective tools for regulating humidity levels; however, accurately assessing their performance, especially for temperate oceanic climates, is yet explicitly unexplored. The current paper presents a packed bed system using water as the working fluid to increase humidity during winter for greenhouse cultivation. An experimental setup is developed, and a detailed parametric study is conducted. Also, an artificial intelligence (AI) based multi-layer perceptron neural network (MLPNN) is designed to evaluate the performance of packed bed systems under varying environmental conditions with different inlet air flow rates (176 m³/hr, 286 m³/hr, 383 m³/hr, and 428 m³/hr). The results show that the system achieves a significant 50% increase in humidity ratio, transitioning from an inlet humidity ratio of 6 g/kgda to an outlet ratio of 9 g/kgda when operating with water at an average temperature of 15.7°C and a flow rate of 12.8 kg/min. The MLPNN is trained with 112 non-repeated datasets and observed that a topology of 2-10-10-1 includes 2 input neurons, 2 hidden layers with 10 neurons each, and 1 output neuron, has high prediction accuracy in estimating Δωa values for the packed bed system. The predictions closely align with experimental data, showing a maximum discrepancy within ±2.5%. This research advances the use of packed bed systems by providing a comprehensive framework for assessing and improving humidity control in greenhouse environments.

Assessing the Impact of Transport Phenomena on Modeling and Optimization of Solid-State Fermentation for the Revalorization of Agro-Industrial Residues in a Wall‐Cooled Packed‐Bed Bioreactor

This work assesses the influence of transport phenomena on the growth of Yarrowia lipolytica 2.2ab (Yl2.2ab) and protease production during Solid-State Fermentation (SSF) in a bench-scale wall-cooled tubular bioreactor packed with substrate-based pellets derived from agro-industrial residues. Our engineering methodology, in a novel manner, includes: (i) developing a new pseudo-heterogeneous model, (ii) identifying and quantifying the impact of all transport phenomena on microbial kinetics, (iii) elucidating how fluid dynamics enhances heat and mass transfer processes, and hence microbial kinetics, and (iv) determining the operational and geometric parameters for optimal bioreactor performance. As main results: (i) all transport phenomena occurring within the bench-scale bioreactor are fundamental for its reliable simulation and will be essential for its scale-up, and (ii) the maximum production of proteases, 420 U kgDS‐1−1, is achieved under the following operational conditions: a tube to particle diameter ratio of 5.6, a bath temperature of 45°C, an inlet airflow rate of 1 L min−1, and inlet fluid temperature of 43 °C. Finally, the pseudo-heterogeneous model is assessed by describing SSF-based observations from the literature, appropriately predicting the performance of Yl2.2ab in a bench-scale bioreactor. These results pave the way for future exploration of Yl2.2ab in SSF within larger-scale packed-bed bioreactors.

Analysis of energy and exergy of lavender extract powder in spray dryer

AbstractIn recent years, the research in the field of medicinal plants as therapeutic supplements has increased significantly. Lavender extract is widely used among medicinal plant products due to its unique therapeutic properties. Since drying processes require high energy, this study was conducted to study the performance of the spray dryer in the production of lavender extract powder at three levels of air temperature 150°C, 180°C, and 210°C, three levels of compressed air flow rate 6, 8, and 10 L/min and ratios of maltodextrin‐drying aid to the mass of dry matter of the extract 0%, 25%, and 50% by response surface method. For this purpose, the energy efficiency and exergy of the powder production process were examined. According to the obtained results, increasing the inlet air temperature and the inlet air flow rate increased the energy efficiency and exergy and decreased the energy efficiency and exergy, respectively. The energy efficiency of the drying process varied in the range of 6.55%–15.87%, and the exergy efficiency () of the drying process in the range of 2.87%–5.84%. Also, the of the spray dryer was calculated in the range of 20.05%–38.78%. Based on the energy efficiency and exergy, the optimal production of lavender plant extract powder was obtained at the air temperature of 210°C, the compressed air flow rate of 6 L/min, and the amount of drying aid of 11.9 g/L.

Efficient construction of self-assembled starch colloidosomes for controlled-release of pesticides

Biodegradable colloidosomes have attracted increasing attention for their applications to enhance the efficacy and reduce wastage of pesticides in agriculture. In this study, we present a continuous and highly efficient method for production of starch colloidosomes. The starch particles with an average particle size of 230.2 nm and good dispersibility were prepared using surface modification technology, and then used as environment-friendly shell materials to form self-assembled starch colloidosomes using spray drying technology. The influences of inlet temperature, feed rate and air flow rate on the morphologies of colloidosomes were also studied. This strategy enables the construction of starch colloidosomes with uniform spherical morphology and controllable pore sizes under different pH, and can be used for pesticide encapsulation. After loading pyraclostrobin (PYR), the regular spherical colloidosomes not only achieve a small mean diameter of 2.35 µm, but also realize a high encapsulation efficiency of 82 %. The release performance of PYR has an obvious pH response and follows the segmented Ritger-Pepapes model of sustained-release. The colloidosomes were used to prevent the photodegradation of pesticides. The PYR loaded colloidosomes exhibit excellent UV resistance with a retention rate of 72.7 %. In addition, the loading of Fe3O4 nanoparticles and the embedding of carbon dots were also explored.

Heat transfer within a multi-package: Assessing the impact of package design on the cooling of strawberries

Perishable horticultural products may necessitate multi-packaging for preservation. The optimized primary and secondary packaging designs allow to reduce cooling time and ensure uniform product temperature, thereby enhancing fruit quality. This study examined how the secondary package design impacts the cooling of strawberries in airtight clamshells (AC) during precooling. The AC design simulates heat transfer within Modified Atmosphere Package (MAP) where there is no direct interaction between the external cooling air and the internal environment of the clamshell. Laboratory experiments were conducted to simulate one level of a pallet, using artificial material instead of real strawberries in order to have a better control of thermophysical properties and thus to better investigate heat transfer mechanisms. The thermal performance of an existing tray design was compared to three new alternative designs. The effect of air headspace, vent holes area and inlet airflow rate on the cooling efficiency was investigated.Experimental results revealed significant cooling heterogeneities among different AC positions, with the largest observed disparities being 1.8 h for half cooling time (HCT) and 3.7 h for seven-eight cooling time (SECT) in the current tray design. Incorporating vent holes into the current commercialized tray design demonstrated superior cooling performance, with 8% improvement of the overall average HCT. Analysis showed increasing the thickness of the air headspace above the AC increased 91% and 113% the overall average HCT and SECT, respectively. The research found that airflow distribution in a tray has a critical effect on the heat transfer between the AC walls and the surrounding air temperature. Thus, the packaging design is crucial in ensuring proper ventilation around the ACs.The alternative designs or operating under a lower airflow rate revealed a potential to cut down on energy use for ventilation. Specifically, when the airflow rate was reduced by one-quarter, there was a remarkable 94% decrease in energy usage. However, this benefit is counterbalanced by a 100% increase in the overall average HCT, which might adversely affect the product quality. Hence, optimizing the packaging design is essential to ensure the right balance between energy efficiency and product quality.The HCT exhibited a linear correlation with the external resistance, which is influenced by the airflow behavior, whatever the AC positions and tray designs.

Exploration of proton exchange membrane fuel cell performance under dynamic humidification conditions

Controlling the relative humidity is crucial for improving fuel cell performance in self-humidifying fuel cells. In light of this, this study investigates the influence of humidity variation on Proton Exchange Membrane Fuel Cells (PEMFC) performance through single-cell testing and a two-dimensional two-phase model. In the experiment, different humidity conditions are achieved by adjusting the inlet air temperature, and the effect of relative humidity on cell performance is observed. The research findings indicate that as the relative humidity increases, the performance of the fuel cell gradually improves. Increasing humidity reduces voltage fluctuations, particularly at low flow rates, demonstrating more stable performance. Under different humidity conditions, when the inlet air flow rate exceeds a certain value, the voltage non-uniformity of the cell remains within 1, indicating insignificant voltage fluctuations, attributed to the effects of inlet air flow rate on performance improvement and alleviation of flooding phenomena. Analysis of the two-dimensional two-phase model reveals that liquid water impedes gas mass transfer, with gas transport under the rib particularly affected. Increasing the flow rate helps remove liquid water under the rib, promoting cell performance stability.

The effect of spray drying parameters on drying of magnesium silicate hydroxide microspheres

Magnesium hydroxide silicate (MSH), as an antiwear additive for lubricating oil, effectively solves the problem that conventional additives contain chlorine, phosphorus and sulfur, which are harmful to environment. However, it is ineffective to prepare MSH powder by traditional drying combined with mechanical ball milling. So the purpose of this study is to prepare smooth MSH microspheres with controllable particle size and moisture content by adjusting spray drying parameters based on hydrothermal synthetic MSH suspension. Results showed that the particle size of MSH microsphere was reduced from 5.5 ± 2.9 μm to 2.78 ± 1.37 μm, and the moisture content was reduced from 7.3% to 4.43% by decreasing solid-liquid ratios and rotating speed of peristaltic pump, or raising inlet temperature of hot air, flow rate of compressed gas and inlet air. In addition, due to the surface energy difference at the interface between liquid-gas and solid-gas during the drying process, nano flaky MSH continuously moved to the center of the droplet, and the capillary force generated by gaps between MSH nanosheets discharges the moisture in the wet core, so that the MSH nanosheets gather and finally form dense and smooth MSH microspheres.

Minimum Air Cooling Requirements for Different Lithium-ion Battery Operating Statuses

Abstract Batteries play an important role in increasing the use of renewable energy sources. Owing to the temperature sensitivity of lithium-ion batteries (LIBs), battery thermal management systems (BTMSs) are crucial to ensuring the safe and efficient operation of LIBs. Researchers have mainly focused on evaluating the performance of BTMS; however, little attention has been paid to the minimum cooling requirements of LIBs, which are important for optimizing the design and operation of BTMSs. To bridge this knowledge gap, the aim in this study was to determine the minimum air cooling requirements for different LIBs operating statuses based on computational fluid dynamics simulations. The inlet airflow rate had the strongest influence. For the studied cases, when the battery operates at charge/discharge (C) rate of three or below, the inlet temperature should be set below 35 °C, and the gap between the batteries should be greater than 3 mm to meet the minimum heat dissipation requirement. At a C-rate of 0.5C, natural convection is sufficient to meet the cooling needs, whereas at 1C or higher rates, forced convection is required. Increasing the number of batteries from six to eight has little impact on the inlet flow required to accommodate the battery heat dissipation.

Performance assessment of packed bed systems for humidity control in greenhouse applications: An experimental-based AI modeling approach

Optimal humidity control is essential for enhancing crop yields and ensuring favorable growth conditions in greenhouse agriculture. Packed bed systems have emerged as effective tools for regulating humidity levels, yet accurately assessing their performance remains unexplored, especially for temperate oceanic climates. This paper presents a packed-bed system with water as the working fluid to increase the humidity level during the winter for greenhouse cultivation. Accordingly, an experimental setup is developed, and a detailed parametric study is conducted. Further, an artificial intelligence (AI)-based modeling approach is developed for evaluating the performance of packed bed systems for greenhouse applications under varying environmental conditions with various inlet air flowrates, such as 176 m³/hr, 286 m³/hr, 383 m³/hr, and 428 m³/hr. Operating with water at an average temperature of 15.7 °C and a flow rate of 12.8 kg/min, the system achieves a significant 50% increase in humidity ratio, transitioning from an inlet humidity ratio of 6 g/kgda to an outlet ratio of 9 g/kgda, indicating its efficiency in elevating air humidity levels. The multi-layer perceptron neural network, trained with 112 non-repeated datasets and employing a 2-10-10-1 topology, demonstrates high accuracy and resilience in estimating Δωa values for the packed bed system, with predictions closely aligning with experimental data and exhibiting a maximum discrepancy within ± 2.5%. This research contributes to the advancement of precision agriculture practices by providing a comprehensive framework for assessing and improving humidity control in greenhouse environments.

Efficient Design of Battery Thermal Management Systems for Improving Cooling Performance and Reducing Pressure Drop

The air-cooled system is one of the most widely used battery thermal management systems (BTMSs) for the safety of electric vehicles. In this study, an efficient design of air-cooled BTMSs is proposed for improving cooling performance and reducing pressure drop. Combining with a numerical calculation method, a strategy with a varied step length of adjustments (∆d) is developed to optimize the spacing distribution among battery cells for temperature uniformity improvement. The optimization results indicate that the developed strategy reduces the optimization time by about 50% compared with a strategy using identical ∆d values while maintaining good performance of the optimized system. Furthermore, the system’s pressure drop does not increase after the spacing optimization. Based on this characteristic, a structural design strategy is proposed to improve the cooling performance and reduce the pressure drop simultaneously. First, the appropriate flow pattern is arranged and the secondary outlet is added to reduce the pressure drop of the system. The results show that the BTMS with U-type flow combined with a secondary outlet against the original outlet can effectively reduce the pressure drop of the system. Subsequently, this BTMS is further improved using the developed cell spacing optimization strategy with varied ∆d values while the pressure drop is fixed. It is found that the final optimized BTMS achieves a battery temperature difference below 1 K for different inlet airflow rates, with the pressure drop being reduced by at least 45% compared with the BTMS before the optimization.

Numerical study on the uniform distribution of flow field of airflow dryer

The uniformity of hot air flow inside the airflow dryer not only affects the moisture distribution at the outlet, but also affects the quality of the product. Based on the guide plate structure of the SH23A airflow tobacco dryer, a gradient curved guide plate dryer is designed, and the flow field distribution of the dryer is numerically investigated under different flow distribution conditions at the hot air inlet and flue gas inlet. The results show that the airflow uniformity is affected by the flow distribution at the inlet of the heated air and the inlet of the cigarette smoke, the structure of the guide plate, etc., the non-uniformity coefficient decreases with the increase of hot air inlet flow rate. The non-uniformity coefficient of tapered arc deflector decreases by 9–12 %.

Transient multi-objective optimization of solar and fuel cell power generation systems with hydrogen storage for peak-shaving applications

The present article introduces an innovative solution to improve performance efficiency while shaving the demand during peak hours. The idea focuses on efficient gas turbine and Rankine cycle hybridization for power and hydrogen production based on high-temperature heliostat solar towers. The proposed model is simulated via TRNSYS software to assess the performance transiently and then optimized through the artificial neural network in MATLAB program to minimize the calculation time. The key economic, environmental, and energy indicators are evaluated, compared, and optimized for this. According to the effect of main design parameters, including gas turbine inlet temperature, mass flow rate, and heliostat area, on the system's indicators, there is a conflictive trend among the power productivity, cost, and emission index, signifying the optimization significance. The optimization results show that the net power, efficiency, cost, and CO2 emissions are 298,300 GJ, 30.7%, 3.6 M$, and 20,760 tonnes under optimal conditions. This working condition is obtained by electing turbine inlet temperature, solar area, and airflow rate of 1087 °C, 91,200 m2, and 68,817, respectively. At this condition, while 71.18% of the yearly primary energy is provided by the sun, biomass meets the rest, showing the importance of renewable combination to achieve the highest independence from the grid. Finally, the system can generate an additional 585 kg/day of hydrogen that could be used in relevant industries.

Performance evaluation of a vertical-finned microchannel and a fin-tube heat exchangers under wet and frosting conditions

This paper compares the performance of a vertical-finned microchannel heat exchanger (VMHX) and a 2-row fin-tube heat exchanger (FTHX) under wet and frosting conditions. The VMHX features vertically oriented fins with an extension at the windward side and parallel microchannel tubes, allowing for efficient water drainage and better performance than conventional microchannel heat exchangers with parallel serpentine fins. However, the performance of the VMHX has not been sufficiently compared to that of FTHX. After conducting experiments under specific operating conditions, the VMHX exhibits better water drainage performance than the FTHX at higher inlet air velocities, higher maximum heat flow, and time-integrating heat flow under certain operating conditions. Although the heating time is relatively shorter than the 2-row FTHX, these results suggest that the VMHX may be a more suitable option for applications requiring efficient water drainage and heat transfer. Additionally, the operating conditions significantly affect the heat exchanger's performance. The performance of VMHX is analyzed under different inlet air velocities, inlet air temperatures, and evaporation temperatures. The results indicate that frost itself had no effect on the heat exchanger performance and that the decrease of the inlet air flow rate was the main factor that decreased the heat exchanger performance. Overall, the results of this study provide valuable insights into the performance of VMHX and FTHX under wet and frosting conditions and the impact of various operating parameters on VMHX performance. These findings can inform the development of more efficient and reliable heat exchangers for various applications.

Simulation and experimental research on the optimization of airflow organization and energy saving in data centers using air deflectors

The airflow organization of the data center directly affects the temperature control performance and the energy efficiency of the cooling equipment. The servers at the bottom of the rack usually suffer from insufficient airflow rate and poor cooling effect. This is because of the limited distance between the bottom servers and the perforated floor, and the small horizontal velocity of the supply air flow. This study aims to improve the uniformity of the cooling airflow in the vertical direction of the rack by the air deflectors, thereby further improving the overall airflow organization in the data center. The size and installation of the deflectors in the data center were optimized according to both the experiment and numerical simulation results. From the results, it is recommended to install the deflector with a width of 100 mm at an angle of 45° under the perforated floor for the rack with the single-side airflow supply. For the rack with the double-side airflow supply, the width of the deflector should be 100 mm and installed at an angle of 30° to the perforated floor to achieve the best airflow distribution. Consequently, the intake airflow rate for the bottom servers significantly increased, and the occurrence of the local hot spots was effectively reduced. The numerical simulation of the airflow organization with and without the deflector was conducted by ANSYS. The results show that, the installation of the deflectors increased the inlet airflow rate for the rack by 16.98% and improved the energy efficiency of the dater center air conditioners by 1.98%.

Data-Based Modeling, Multi-Objective Optimization and Multi-Criteria Decision Making of a Catalytic Ozonation Process for Degradation of a Colored Effluent

In the catalytic ozonation process (COP), the reactions are complex, and it is very difficult to determine the effect of different operating parameters on the degradation rate of pollutants. Data-based modeling tools, such as the multilayer perceptron (MLP) neural network, can be useful in establishing the complex relationship of degradation efficiency with the operating variables. In this work, the COP of acid red 88 (AR88) with Fe3O4 nano catalyst was investigated in a semi-batch reactor and a MLP model was developed to predict the degradation efficiency (%DE) of AR88 in the range of 25 to 96%. The MLP model was trained using 78 experimental data having five input variables, namely, AR88 initial concentration, catalyst concentration, pH, inlet air flow rate and batch time (in the ranges of 150–400 mg L−1, 0.04–0.4 g L−1, 4.5–8.5, 0.5–1.90 mg min−1 and 5–30 min, respectively). Its optimal topology was obtained by changing the number of neurons in the hidden layer, the momentum and the learning rates to 7, 0.075 and 0.025, respectively. A high correlation coefficient (R2 > 0.98) was found between the experimental and predicted values by the MLP model. Simultaneous maximization of %DE and minimization of Fe3O4 concentration was carried out by multi-objective particle swarm optimization (MOPSO) and the Pareto-optimal solutions were successfully obtained. The trade-off was analyzed through multi-criteria decision making, and one Pareto-optimal solution was selected. The developed model and optimal points are useful for treatment of AR88 wastewater.

Air flow prediction and evaluation of ventilation effectiveness with different zonal configurations

This paper proposes a numerical method for the study of ventilation efficiency in buildings. The developed model is validated with the experimental results of Nielsen [5] who tested the isothermal flow in a scaled model of a ventilated room. A zonal method is used to predict airflow patterns in the same ventilated room. The different equations governing the flow in the room were coded in Matlab for different operating conditions, different zonal configurations of the room and different number of cells (control volumes). The efficiency of the ventilation was determined by calculating the number of air changes per hour (ACH) for each cell. The present results show the importance of the inlet air flow rate, the space resolution and the jet inlet dimensions on the determination of air quality.