Fluent Simulation Research Articles

Effect of Sewage Sludge Addition on the Co-Combustion Characteristics of Municipal Solid Waste Incineration

This study employs a numerical computation model based on a municipal solid waste (MSW) incinerator in Nanning to investigate the impact of different sewage sludge (SS) co-combustion ratios and MSW incinerator temperatures on combustion efficiency. Using the FLUENT simulation method, this study systematically analyzes the distribution characteristics of the temperature field, velocity field, and pollutant concentration field within the furnace under various SS mixing ratios (5%, 7%, 10%, and 15%) and MSW incinerator temperatures (800 K, 1000 K, and 1200 K). The simulation results indicate that the combustion efficiency was optimal at an MSW incinerator temperature of 800 K, where the co-combustion of SS with MSW mixed effectively, leading to a stable and efficient combustion process. Furthermore, an SS co-combustion ratio of 7% was identified as the most effective in maintaining high combustion efficiency. These findings contribute to the optimization of co-combustion strategies for MSW and SS, enhancing both operational efficiency and environmental compliance.

Integrating ANSYS Fluent Simulation and Aspen Plus for efficient heavy metal ion removal with de-oiled cake

In this study bio-flocculant extracted from the de-oiled cake, a common waste generated while producing oil was used to treat an electroplating industrial effluent. A comprehensive analysis of flocculation efficiency in a simulated reactor using ANSYS Workbench - Fluent, with a focus on optimizing impeller position was carried out. The findings reveal that the optimal impeller position is 2 cm from the tank base, where maximum turbulent kinetic energy (0.02577 m2/s2) and dissipation rate (22.19 m2/s3) were achieved at 200 RPM, enhancing flocculation efficacy. Furthermore, the study identifies 0.5 g L−1 as the optimal flocculant dosage, resulting in 72.70 % and 89.38 % removal of Ni(II) and Cr(VI), respectively. The flocculation process was determined to follow second-order kinetics, with significant improvements in collision efficiency and particle aggregation at the optimized dosage. Fourier Transform Infrared spectroscopy analysis confirmed chemical interactions leading to flocculation, while zeta potential and particle size distribution studies corroborated the stability and effectiveness of the process. A techno-economic analysis was conducted, estimating the total capital investment required for pilot and industrial-scale implementations, highlighting the feasibility and scalability of the proposed treatment method. A holistic framework for enhancing industrial effluent treatment processes by integrated computational fluid dynamics, kinetic studies, and economic evaluation, is the novelty of this research.

Comparative analysis of performance of different types of Tesla valves

Abstract The Tesla valve is a valve with no moving parts. Its special configuration also allows the pressure drop of fluid passing through the Tesla valve from the reverse inlet to be much greater than the pressure drop of fluid passing through the Tesla valve from the forward inlet. Therefore, the Tesla valve has a certain degree of single pilot connectivity and pressure reduction capability. This article selected 8 common types of Tesla valves, By using numerical calculation method through Fluent simulation, the differences of resistance coefficient, pressure drop and Di value of 8 types of single-stage Tesla valves under three different working conditions were compared. In order to explore the performance of 8 kinds of Tesla valves under the three working conditions. At the same time, the relationship between the flow state and the structure of each part of the fluid before and after passing through the distributary pipe is analyzed. The simulation results show that due to the different structure of various Tesla valves, the flow rate, pressure and turbulent kinetic energy of the fluid inside the valve also have different changes. At the same time, there are many similarities in the flow state of some Tesla valves with similar structural types. Finally, according to the calculation results, the advantages and disadvantages of various types of Tesla valves and their applications are analyzed.

Calculation of in-situ steady-state heat flux on EAST lower divertor

Heat flux is a key issue in tokamak devices. The non-uniform high heat flux on Plasma-Facing Components (PFCs) has led to local severe damage, including cracks and melting, in current tokamaks such as EAST and WEST. To characterize the non-uniform heat flux loading on the divertor surfaces, the parallel incident heat flux q‖, the decay length λq along the radial direction and the Gaussian spreading width S are used. The q‖ can lead to a very high peak heat flux loading on the divertor surfaces, which may cause critical heat flux problems. Additionally, the decay length is a key consideration for future tokamak designs like ITER. Every effort on the present tokamak devices contributes to updating the scaling of the heat flux. In EAST, a calculation method based on a high spatial resolution IR camera is employed to obtain the heat flux and decay length. The main process involves comparing the surface temperature distribution calculated by Fluent simulation with that measured by an infrared camera. Taking a high heating source discharge (#123059 ∼ 10 MW heating source) as an example, the heat flux is as follows: q‖=216-14+19 MW/m2, with λq=6.2-1.1+1 mm, and S=1.2±0.4 mm; it is in line with Langmuir probe data. The infrared-based heat flux calculation method can calculate the peak incident heat flux and the decay length simultaneously, its result can help to update the scaling model of heat flux, thus not only helping to improve the present device but also offering important reference for future tokamaks

Design and multi parameter performance optimization of the bionic robotic fish driven by tail fin

In this paper, we investigate the optimization of body contour parameters and the parameters of the tail fin in bionic robotic fish. A new type of robotic fish with fully flexible shell was proposed, followed by the analysis and optimization of the resistance properties of the profile. Subsequently, a dynamic model considering tail fin deformation was established. We use a combination of Fluent simulation and particle swarm optimization (PSO) algorithm to seek the key parameters for an enchanced performance. Upon multi-parameter performance optimization, the obtained results indicate that the fully flexible shell robotic fish can achieve a high swimming speed of 0.69 m/s (equivalent to 1.2 BL/s) and exhibit excellent turning maneuverability with a turning radius of 0.8 body lengths. This paper provides insights for optimizing the performance of robotic fish and enhancing its underwater operational capabilities.

Research on Carbon Dioxide Computational Fluid Dynamics Simulation of Urban Green Spaces under Different Vegetation Spatial Layout Morphologies

Urban green spaces (UGSs) are considered an important natural approach for improving urban climatic conditions, promoting sustainable urban development, and advancing the global “Carbon Peak and Carbon Neutrality” targets. Previous studies have found that different vegetation spatial morphologies significantly impact the capacity to obstruct and absorb CO2, but it is not yet well understood which morphology can retain and absorb more CO2. This study takes Nantong Central Park as an example and conducts a CFD (Computational Fluid Dynamics) carbon flow simulation for CO2 under different vegetation spatial morphologies to identify their CO2 retention and absorption effects. First, the carbon sink benefits of elements such as “vegetation, soil, and wetlands” within the park were calculated, and the elements with the highest carbon sink benefits were identified. Then, the park was divided into carbon welcoming zones, carbon flow zones, and carbon shadow zones for carbon flow simulation with the highest carbon sink benefits. The results show that in the carbon welcome area, the one-block long fan-shaped plant community with a spatial density of 40 m thickness can best meet the requirements of absorption and induction of a small amount of carbon dioxide, with the smallest air vortex and uniform distribution of carbon dioxide in the surrounding area. In the carbon flow area, combined with the visual effect, the planting pattern of 6 m spacing herringbone combined with natural structure was adopted, which has a good carbon dioxide blocking and absorption capacity. In the carbon-shaded area, a herringbone planting pattern with a total width of 40 m and a base angle of 60° was chosen, which had the strongest hindrance and absorption capacity. Urban park environment optimization can use Fluent simulation to analyze the flow of carbon dioxide between different elements affected by wind dynamics at the same time. Based on the results, the form, layout, and spatial distance are adjusted and optimized. This study can better guide the spatial layout of vegetation and contribute to the realization of the goal of “carbon peak and carbon neutrality”.

Analysis of Longitudinal Braking Stability of Lightweight Liquid Storage Mini-Track Vehicles

In this study, a theoretical model was established for longitudinal braking stability (LBS) of a lightweight liquid storage mini-track vehicle to investigate its behaviors. The influence of the tank liquid filling ratio (TLR), initial velocity (IV), and initial braking deceleration (IBD) on the LBS of the tracked vehicle was studied via FLUENT simulation. The simulation results showed that when the IV and the IBD were constant, the TLR significantly affected the braking efficiency. Conversely, when the TLR was 0.7, the braking efficiency decreased by 32%, resulting in the worst LBS. The braking efficiency at different IVs decreased by ~30% when using a constant IBD and TLR, and the braking stability exhibited little difference. Further, the braking efficiency decreased noticeably with increasing IBD; meanwhile, the braking longitudinal stability worsened. When the IBD was increased to 5 m⋅s−2, the braking efficiency decreased by 48.4%. The road experiment showed that when the tracked vehicle was accelerated and braked under limit conditions, the stability requirements were met. Finally, by combining the simulation and road experiment, the driving parameters of the tracked vehicle that could satisfy the LBS were obtained.

Temporal characteristics of turbulent flow and moth orientation behaviour patterns with fluent simulation and moth-based moving model simulation

ObjectivePrevious research has explored the pheromone release patterns of female moths, revealing species-specific release frequencies and the transmission of temporal information through odourant plumes in turbulent flows. Varying the release frequency during the orientation process results in distinct orientation behaviours. Studies on moth movement patterns have determined that encounters and deviations from odour plumes elicit distinct reactions; the time interval between each movement pattern is measured as the “reaction time,” and the interval between each detection and loss of odourant plume is measured as the “gap length.” MethodsWe simulated turbulent flow at various release frequencies. Our efforts focused on establishing a model that could simulate the joint orientation movement under turbulent flow and intermittent plumes. We built an agent moving mechanism, including wind velocity information, with particular reference to the temporal parameter and orientation success efficiency. ResultsWe calculated the time threshold of each burst in different simulations under different wind velocities and release frequencies. The time structure characteristics of the plume along the turbulent flow vary depending on the distance from the source. We simulated walking agents in a turbulent environment and recorded their behaviour processes. The reaction time, release interval, and time threshold were related to the orientation results. ConclusionOn the basis of previous experimental results and our simulations, we conclude that the designated interval time likely enhances search efficiency. The complex and dynamic natural environment presents various opportunities for using this unique odour-source searching capability in different scenarios, potentially improving the control systems of odour-searching robots.

Simulation and Analysis of Hydrodynamic Behavior in Different Nozzles and Its Corresponding Fluidized Beds

Uniform air distribution is the basic condition for the stable operation of circulating fluidized beds and closely related to the hole layout of nozzles and the air outlet conditions. In this paper, CAD modeling software is used to establish different opening types for nozzles and the corresponding gasifier models, and Fluent simulation software for numerical simulations (k-ε model) is introduced to the hydrodynamic behavior of the upper opening, the side opening and the combined opening types of nozzles, as well as the corresponding single-nozzle fluidized bed gasifiers. The flow field distribution under the above opening modes is obtained, including the velocity distribution, static pressure distribution, and total pressure distribution, and the influence of the boundary conditions, including the inlet gas velocity and outlet pressure, on the flow field distribution inside the nozzle and in the single-nozzle fluidized bed gasifier is also investigated. The simulation results show that the suitable optimal operating conditions for the coal gasifier can be achieved with an inlet velocity of 30 m/s and an outlet pressure of 25 kPaG. Under the above conditions, the local fluidization dead zone at the elbow and top of the nozzle is narrower, the uniformity of the wind velocity can be improved, the pressure drop of the inner core tube of the nozzle is gentle, and the pressure distribution tends to be stable. Theoretically, the anti-slag performance of the nozzle is improved, which will enhance the stability and reliability of the operation of the gasification unit.

Simulation and experimental study of flexible adsorption and localization mechanism for vegetable grafting machines

Because of the lack of good seedling positioning during vegetable grafting, there are issues such as high labor costs and long grafting time. This article proposes a negative pressure suction seedling positioning method for seed leaves based on the characteristic parameters of cucumber spike wood, and designs a flexible adsorption positioning mechanism for spike wood. Firstly, the ventral surface curve trajectories of cucumber cotyledons were extracted using Matlab software, and then a shape-adaptive design was applied to the attachment surface of the flexible suction positioning mechanism, and a computational fluid dynamics model of the airflow field was established. By combining Fluent simulation analysis with orthogonal experiments, the effect of suction hole diameter, vacuum negative pressure value, suction hole quantity, and suction hole depth on the adsorption effect of the suction head was analyzed, the main and secondary factors and operational indicators that affect the adsorption effect are evaluated. The optimal parameter combination: suction hole diameter of 1.5 mm, vacuum negative pressure value of 2 kPa, suction hole quantity of 42, and suction hole depth of 2 mm, has been found. A verification experiment was conducted on a test bench, and the experimental results show that the success rate of leaf absorption using the optimal parameter combination is 97.69%, which indicates that the suction head is designed reasonably and meets the requirements of grafting.

Impact of Air Velocity on Mold Growth in High Temperature and Humidity Conditions: An Experimental Approach

To address the challenges of indoor mold in southern China, this study designed and constructed an innovative experimental system to investigate mold growth in buildings under the combined influence of multiple factors. Using Fluent simulation (Ansys Fluent 19.0), we designed a suitably sized experimental chamber to realistically replicate the effects of factors such as temperature, humidity, and air velocity on mold growth. After establishing and fine-tuning the experimental system, we conducted two preliminary experiments, successfully validating the feasibility of our setup. Additionally, we observed that in a high-temperature, high-humidity environment of 28 °C and 80% relative humidity, the mold growth rate in the experimental chamber increased with the rise in inlet air velocity. This experimental system will serve as the foundation for future studies on indoor mold growth in building spaces in southern China.

A novel vacuum-photovoltaic glazing integrated thermoelectric cooler/warmer for environmental adaptation: thermal performance modelling

Vacuum-photovoltaic glazing, renowned for exceptional thermal insulation and solar energy utilization, faces limitations in its adaptability to varying seasons. While it effectively reduces heat transmission into indoor spaces during summer, it becomes detrimental during winter. To address this challenge, this study introduces an innovative solution: vacuum-photovoltaic-thermoelectric (VPT) glazing, which integrates vacuum, photovoltaic and thermoelectric cooling/warming technologies. The theoretical models were developed and validated through WINDOW and Fluent simulations. A comparative analysis is conducted considering thermal performance under various environmental parameters. The results demonstrate that VPT glazing exhibits enhanced thermal performance, with interior glass temperature decreased by 3.0–9.6oC in summer while increased by 2.5–6.2oC in winter, accounting for ∼55.0 % reduction in air-conditioning load. Compared to vacuum-photovoltaic glazing, VPT glazing reduces the coupling U-value from 7.88 to 5.87 W m−2 K−1 in summer and increases from −0.31 to 2.61 W m−2 K−1 in winter. The solar heat gain coefficient decreases from 0.37 to 0.30 in summer and increases from 0.24 to 0.29 in winter. These results demonstrate the effectiveness of VPT glazing in adapting to different seasons and achieving better thermal environment performance. This study provides insights into VPT glazing design for environmental adaptation and offers implications for future research and applications in energy-efficient building technologies.

Axial flow impeller design and simulation for negative pressure adsorption climbing robot

Abstract Axial flow impeller is broadly applied in negative pressure adsorption climbing robots, but its design method and procedure are rarely reported. This paper used a wind turbine blade climbing NDT robot as case study, presented a comprehensive design process of the axial flow impeller, and evaluated the adsorption performance of the impeller by carrying out simulation experiments. Firstly, analysing the force equilibrium of the robot and determining minimum adsorption force required by the robot. Secondly, defining design parameters of the axial flow impeller by using fluid dynamics analysis method. Thirdly, specifying structural parameters of the impeller blades using impeller design theory and developing the CAD model of the impeller. Finally, evaluating the adsorption performance of the impeller by carrying out a series of Fluent simulation experiments. Research results showed that the total adsorption force of the impeller reached 80.30N as rotational speed is 6000rpm, which satisfied design requirements of the climbing robot. This research provides a methodological framework in designing axial flow impellers for the purpose of negative pressure adsorption.

Modeling the thermally adaptive performance of building exterior walls with linear temperature-dependent thermal conductivity

The concept of adapting to variable external thermal environments by varying the thermophysical properties of building envelopes has gained increased attention in recent years. This study aims to evaluate the thermally adaptive performance of exterior walls incorporating linear temperature-dependent thermal conductivity-based insulation (LTTI). A variant resistance–capacitance nodal model was developed and validated against Fluent simulations, demonstrating high accuracy and time efficiency. The study evaluates the thermally adaptive indices (i.e., the adaptive time lag, adaptive decrement factor, and thermally adaptive ratio) for LTTI-based walls with at different temperature-dependent slopes under the Beijing climate. The results show that the dynamic thermal indices follow a parabolic pattern, whereas the monthly adaptive indices exhibit a folded line pattern with the extreme value in July. The maximum value for the adaptive time lag and decrement factor reached 3.8 h and 0.003 at −1.0 mW·m−1·K−2, while minimum extreme value is observed at 1.0 mW·m−1·K−2 with −3.8 h and −0.003, respectively. Furthermore, the study determines the relationship between the heating, cooling, and overall thermally adaptive ratios and the seasonal month and the temperature-dependent slope. At a temperature-dependent slope of 1.0 mW·m−1·K−2, the heating, cooling, and overall thermally adaptive ratios were approximately 0.162, −0.045, and 0.160, respectively. These findings suggest that LTTIs with a positive slope adapt to the thermal environment in Beijing, while those with a negative slope exhibit the opposite, anti-adaptive performance. These results could provide insights into the development of energy-efficient and thermally adaptive building envelopes based on LTTI materials.

Validating ANSYS Heat Transfer Models Using Experimental Data Analysis of Two Phase Change Materials with Differing Melting Temperatures

Phase change materials are becoming more and more popular as viable options for improving the thermal performance and energy efficiency of a variety of applications, especially in innovative building envelope designs. In this paper, experimental data from two different phase change materials with differing melting temperatures (21°C and 28°C) are used to validate numerical system heat transfer models. The experimental setup included a heat flux apparatus, which was utilized to ascertain average temperature and heat flow changes over time during both heating and cooling phases for both phase change materials. The data obtained from the experiments were utilized to generate ANSYS Fluent simulation models replicating the experimental setup. The parameters and boundary conditions for the models can be assigned in several ways within ANSYS Fluent software. Consequently, two simulation models were created: one integrated the thermal and physical properties of the experimental setup's system components, while the other utilized the measured heat-flux values over time from the experiments as an input source for calculating average temperatures within the phase change material. The average temperature data from both simulation and experimental results were compared to validate both ANSYS models. By aligning the simulated results with the experimental data, the accuracy and reliability of the numerical models have been established in predicting the thermal behaviour of the two phase change materials. The two numerical system heat transfer models developed in this study serve as valuable tools for conducting further analysis and optimization of systems based on phase change materials. This research highlights the significance of phase change materials in enhancing the thermal performance of building envelopes, particularly in solar energy applications.

Multi-Strategical Thermal Management Approach for Lithium-Ion Batteries: Combining Forced Convection, Mist Cooling, Air Flow Improvisers and Additives

Maintaining the peak temperature of a battery within limits is a mandate for the safer operation of electric vehicles. In two-wheeler electric vehicles, the options available for the battery thermal management system are minuscule due to the restrictions imposed by factors like weight, cost, availability, performance, and load. In this study, a multi-strategical cooling approach of forced convection and mist cooling over a single-cell 21,700 lithium-ion battery working under the condition of 4C is proposed. The chosen levels for air velocities (10, 15, 20 and 25 m/s) imitate real-world riding conditions, and for mist cooling implementation, injection pressure with three levels (3, 7 and 14 bar) is considered. The ANSYS fluent simulation is carried out using the volume of fluid in the discrete phase modelling transition using water mist as a working fluid. Initial breakup is considered for more accurate calculations. The battery’s state of health (SOH) is determined using PYTHON by adopting the Newton–Raphson estimation. The maximum temperature reduction potential by employing an airflow improviser (AFI) and additives (Tween 80, 1-heptanol, APG0810, Tween 20 and FS3100) is also explored. The simulation results revealed that an additional reduction of about 11% was possible by incorporating additives and AFI in the multi-strategical approach. The corresponding SOH improvement was about 2%. When the electric two-wheeler operated under 4C, the optimal condition (Max. SOH and Min. peak cell temp.) was achieved at an air velocity of 25 m/s, injection pressure of 7 bar with AFI and 3% (by wt.) Tween 80 and a 0.1% deformer.

Optimizing Efficiency of Tea Harvester Leaf-Collection Pipeline: Numerical Simulation and Experimental Validation

To address the challenges of missed and disorderly picking in tea harvesters, this study focused on the leaf-collection pipeline and utilized Fluent simulation 19.0 software. A single-factor test identified key parameters affecting airflow velocity. An orthogonal test evaluated the main pipe taper, number of branch pipes, and branch pipe outlet diameter, with average outlet wind speed and wind speed non-uniformity as indicators. The optimal parameters were a main pipe taper of 25.5 mm, 10 branch pipes, and an inner diameter of 17.10 mm for the outlet, resulting in 10.73 m/s average wind speed and 8.24% non-uniformity. Validation tests showed errors under 1%. Further optimization on the internal structure’s extension length led to 11.02 m/s average wind speed and 8.04% non-uniformity. Field experiments demonstrated a 3.40% stalk leakage rate and 90.36% bud leaf integrity rate; the optimized structure of the leaf-collecting pipeline significantly improved the uniformity of airflow and the picking efficiency. These findings offer valuable insights and practical benefits for enhancing the efficiency of tea harvesters.

Research on Ventilation Simulation Technology for Large Section Gas Tunnel Construction

In order to solve the problem of gas overrun during the construction of large section gas tunnel, this paper takes the Baima Tunnel as the engineering background and uses fluent numerical simulation software to study the gas transport law of the tunnel under different ventilation methods. The results indicate that when the tunnel is excavated for 1200m, the forced ventilation method cannot effectively solve the problem of gas overrun on the heading face. After adopting the gallery ventilation method, the gas concentration on the heading face decreases to less than 1%, which effectively solved the problem of gas overrun on the heading face and provided assistance for the safe construction of the project..

Study of spatiotemporal evolution of coupled airflow–gas–dust multi-field diffusion at low-gas tunnel

The increasing level of mechanization in coal mining means more dust and gas are generated during excavation operations in tunnels. The high concentrations of dust and gas severely affect production efficiency and the physical and mental health of workers. Here, Ansys Fluent simulations were performed to derive the spatiotemporal evolution of coupled airflow–dust–gas diffusion in a low-gas excavation face. The aim was to optimize pollution control by determining the optimal duct distance, L, from the working face in the excavation tunnel. Our results showed that the airflow field affects the coupled diffusion and transport of dust and gas. According to a comparison of the effects of different duct distances from the working face, when L = 6 m, the average dust concentration in the tunnel is low (257.6 mg/m3), and the average gas concentration in the tunnel is 0.28 %, which does not exceed the safety limit. Accordingly, the optimal distance of the duct for pollution control is 6 m. The results of field measurements supported the validity of the simulation. Our findings can be used to improve the air quality in tunnels, thereby keeping miners safe and the working area clean.

Design and performance analysis on a breathing-type instant heat recovery module for fresh air ventilation

The process of air exchange in buildings is essential for maintaining optimal indoor air quality. However, this process results in the loss of thermal energy in the form of sensible heat carried by the air, thereby increasing the energy demand of the buildings. In order to recover this thermal energy, the present study introduces a breathing-type instant heat recovery module for fresh air ventilation, inspired by the biological nasal breathing process. The performance of this module was thoroughly investigated through Fluent simulation and experimental tests. Based on the simulation results, the module exhibits the capability to decrease the outdoor air temperature by an average of 7.5 ℃ prior to its entry into the room. Consequently, this leads to a daily energy conservation of approximately 2.354 kW·h, accompanied by an energy recovery rate of 62.9 % under typical summer conditions. Notably, the heat recovery performance is more favorable during winter, resulting in daily energy savings of about 5.446 kW·h and an energy recovery rate of 62.2 %. The conducted experiments substantiate that the module is able to recuperate approximately 70 % of heat when the indoor temperature is set at 22 °C, while the outdoor temperature reaches its lowest point at 6 °C. The study describes an effective heat recovery technology for building air exchange using a breath-type instant heat recovery module. This could offer a new energy-saving solution for the renovation of fresh air systems.