Flow Direction Control Research Articles

An Intelligent Diagnostic Method for Wear Depth of Sliding Bearings Based on MGCNN

Sliding bearings are vital components in modern industry, exerting a crucial influence on equipment performance, with wear being one of their primary failure modes. In addressing the issue of wear diagnosis in sliding bearings, this paper proposes an intelligent diagnostic method based on a multiscale gated convolutional neural network (MGCNN). The proposed method allows for the quantitative inference of the maximum wear depth (MWD) of sliding bearings based on online vibration signals. The constructed model adopts a dual-path parallel structure in both the time and frequency domains to process bearing vibration signals, ensuring the integrity of information transmission through residual network connections. In particular, a multiscale gated convolution (MGC) module is constructed, which utilizes convolutional network layers to extract features from sample sequences. This module incorporates multiple scale channels, including long-term, medium-term, and short-term cycles, to fully extract information from vibration signals. Furthermore, gated units are employed to adaptively assign weights to feature vectors, enabling control of information flow direction. Experimental results demonstrate that the proposed method outperforms the traditional CNN model and shallow machine learning model, offering promising support for equipment condition monitoring and predictive maintenance.

A 3D printed acoustofluidic nozzle-diffuser microfluidic pump

Microfluidic flow control systems are critical components for on-chip biomedical applications. This study introduces a new micropump for on-chip sample preparation and analysis by using an acoustic nozzle diffuser mechanism. The micropump implements a commercially available transducer and control board kit with 3D-printed fluid reservoirs. In this micropump, conic-shaped micro-holes on the metal sheet cover of the transducer are employed as oscillating nozzle diffuser micro arrays to achieve directional flow control. The micropump is shown to efficiently pump water and particle mixtures exceeding flow rates of 515 µl/min at a 12-volt input voltage. In addition, owing to the small size of the nozzle hole opening, larger particles can also be filtered out from a sample solution during fluid pumping enabling a new function. Importantly, the micropump can be fabricated and assembled without needing a cleanroom, making it more accessible. This feature is advantageous for researchers and practitioners, eliminating a significant barrier to entry. By combining commercially available components with 3D printing technology, this micropump presents a cost-effective and versatile solution for on-chip applications in biomedical research and analysis.

Research on circulating heat recovery law of single horizontal well for hot dry rock geothermal resources

Hot dry rock is essential to geothermal resources because of its advantages of clean green, good stability, large reserves, and high utilization coefficient. However, there are few large-scale and commercial mining schemes due to increased development costs, induced earthquakes, and low recovery during fracturing. Based on the above background, the concept of hot dry rock development for circulating heat recovery in the single horizontal well is put forward, injection and recovery of circulating working fluid are realized by single horizontal well, interchange of hollow pipe in well with liquid flow passage in wall annulus is realized by the fast connection of flow passage transformation, and flow direction control of thermal fluid is recognized by its unique bottom hole structure, to achieve the goal of cleanliness, low energy consumption, and high-efficiency heat recovery, to achieve the purpose of avoiding a series of problems caused by reservoir fracturing. A mathematical model has been created to calculate heat recovery efficiency in a single horizontal well. This model analyzes the impact of critical parameters in mining hot dry rock geothermal resources from single horizontal wells. The results show that the flow rate of circulating working fluid, the wellbore’s horizontal section length, and the formation’s thermal conductivity greatly influence thermal recovery. For instance, a domestic hot dry rock project can recover heat up to 3.08 MW through cyclic mining with a single horizontal well over 30 years.

Coupling the Relationship between Land Subsidence and Groundwater Level, Ground Fissures in Xi’an City Using Multi-Orbit and Multi-Temporal InSAR

The Xi’an region of China has been suffering from groundwater depletion, ground fissure hazards, and surface subsidence for a long time. Due to the complex tectonics and frequent human and natural activities, land deformation in the region is aggravated, posing a threat to infrastructure and human life. This study adopted the multi-orbit and multi-temporal InSAR technology to measure multi-dimensional displacements and time-series displacements in Xi’an City. Through the multi-dimensional deformation verification, it was found that the control of groundwater flow direction by ground fissures is the cause of horizontal deformation. On the contrary, the flow direction of groundwater from west to east was inferred using multi-dimensional deformation. Further analysis was performed by calculating the deformation gradient of the cumulative deformation to obtain differential land subsidence and angular distortions, and it was quantitatively determined that the threshold for the generation of ground fissures caused by differential subsidence is 1/500. Then, through the mutual verification of the time series data and the groundwater level, a positive correlation was obtained. However, due to the inconsistent geological conditions and soil layers at the monitoring positions of Well 2 and Well 3, the lag time was 64 days and 4 days, respectively. Finally, the relationship between the surface deformation and the groundwater in the sustained uplift areas was explored. The Well 1 groundwater-level data with a monitoring period of 22 years and the corresponding monitoring points’ time series data were modeled; it was concluded that, in the future, the groundwater level will continue to rise and surface deformation will mainly increase, without a slowing trend. Therefore, research on the impact of surface uplift on infrastructure should be strengthened. By quantifying the relationship between land subsidence, ground fissures, and the groundwater level in Xi’an, the results of this study provide a reference for groundwater monitoring and management.

A Novel Active Cooling System for Internal Combustion Engine Using Shape Memory Alloy Based Thermostat.

Pollutants in exhaust gases and the high fuel consumption of internal combustion engines remain key issues in the automotive industry despite the emergence of electric vehicles. Engine overheating is a major cause of these problems. Traditionally, engine overheating was solved using electric pumps and cooling fans with electrically operated thermostats. This method can be applied using active cooling systems that are currently available on the market. However, the performance of this method is undermined by its delayed response time to activate the main valve of the thermostat and the dependence of the coolant flow direction control on the engine. This study proposes a novel active engine cooling system incorporating a shape memory alloy-based thermostat. After discussing the operating principles, the governing equations of motion were formulated and analyzed using COMSOL Multiphysics and MATLAB. The results show that the proposed method improved the response time required to change the coolant flow direction and led to a coolant temperature difference of 4.90 °C at 90 °C cooling conditions. This result indicates that the proposed system can be applied to existing internal combustion engines to enhance their performance in terms of reduced pollution and fuel consumption.

A thermal management system for an energy storage battery container based on cold air directional regulation

The existing thermal runaway and barrel effect of energy storage container with multiple battery packs have become a hot topic of research. This paper innovatively proposes an optimized system for the development of a healthy air ventilation by changing the working direction of the battery container fan to solve the above problems. Four ventilation solutions based on fan flow direction control are numerically simulated, and their internal airflow distribution and thermal behavior are analyzed in detail. The results show that the heat dissipation effect of optimized solution 4 is significantly better than other solutions, and its average temperature and maximum temperature difference are 310.29 K and 4.87 K. The results are reduced by 1.16 % and 54.36 % respectively compared with the initial scheme. The results show that optimized solution 4 has significantly better heat dissipation than the other solutions, with an average temperature and maximum temperature difference of 310.29 K and 4.87 K respectively, a reduction of 1.16 % and 54.36 % respectively compared to the initial scheme. In summary, the cooling and ventilation solution based on the logical control of the fan direction is feasible and had a certain market prospect due to its simple structure and high economy.

A combined melt-stretching and quenching setup for experimental studies of polymer crystallization under complex flow-temperature environments.

A combined melt-stretching and quenching setup is designed and developed to allow experimental investigations of polymer crystallization under the complex flow-temperature environments comparable to those encountered in the actual industrial processing. The melt-stretching proceeds by two drums rotating in the opposite directions with simultaneous recording of a stress-strain curve, where the Hencky strain and strain rate (≤233s-1) are adjustable over a large range. After stretching, liquid N2 is used as a cooling medium to quench the free-standing melt, which is sprayed directly to the deformed melt driven by an electric pump. To ensure a high cooling efficiency, a three-way solenoid valve is employed to execute a sequential control of the liquid N2 flow direction to reduce the boil-off of liquid N2 before entering the sample chamber. The melt cooling rate depends on the liquid N2 flow rate controlled by a flow valve, which is up to 221 °C/s when quenching the isotactic polypropylene (iPP) melt with a thickness of 0.28mm at 150 °C. Two independent temperature control modules are designed to meet the requirements of different stages of melt-stretching and quenching. To verify the capability of the setup, we have performed the melt-stretching and quenching experiments on iPP samples. The setup is demonstrated to be a valuable new tool to study polymer crystallization under coupled flow-cooling fields.

Peculiarities of Integrating Mechanical Valves in Microfluidic Channels Using Direct Laser Writing

Regenerative medicine is a fast expanding scientific topic. One of the main areas of development directions in this field is the usage of additive manufacturing to fabricate functional components that would be later integrated directly into the human body. One such structure could be a microfluidic valve which could replace its biological counterpart in veins as it is worn out over the lifetime of a patient. In this work, we explore the possibility to produce such a structure by using multiphoton polymerization (MPP). This technology allows the creation of 3D structures on a micro- and nanometric scale. In this work, the fabrication of microfluidic systems by direct laser writing was carried out. These devices consist of a 100 μm diameter channel and within it a 200 μm long three-dimensional one-way mechanical valve. The idea of this device is to have a single flow direction for a fluid. For testing purposes, the valve was integrated into a femtosecond laser-made glass microfluidic system. Such a system acts as a platform for testing such small and delicate devices. Measurements of the dimensions of the device within such a testing platform were taken and the repeatability of this process was analyzed. The capability to use it for flow direction control is measured. Possible implications to the field of regenerative medicine are discussed.

Simulating inter-individual contact in the inter-station passenger transfer system connecting multiple metro stations based on space–time path data

Determining passengers’ inter-individual contact in the metro station area (MSA) is an important issue to simulate and mitigate the spread of the Coronavirus disease 2019 (COVID-19) pandemic. Taking the inter-station passenger transfer system (IPTS) as an example, this study aimed to verify the passenger flows’ influence on the inter-individual contact around the MSA. Based on actual observed data, the passengers’ space–time paths (STP) in the network were obtained through an agent-based simulation. In this study, the direct contact model and the mediate contact model were used to describe the inter-individual contact in view of the passengers’ STP. The contact count and the exposure duration were defined as indicators to measure the contact degree of individual and the system. The results show that the time-varying trip distribution of the metro passengers significantly affected the inter-individual contact degree and the spatial distribution of contact risk region in the MSA. The intersection of passenger flow in different directions and the concentrated movement of passenger flow in the same direction increased the inter-individual contact and prolonged exposure in the morning. Through simulation experiments, the study verified the effects of controlling the flow direction and equalizing passenger flow generation measures aiming to reduce inter-individual contact and cumulative exposure duration.

Introducing bioflocculation boundaries in process control to enhance effluent quality of high-rate contact-stabilization systems.

High-rate activated sludge (HRAS) systems suffer from high variability of effluent quality, clarifier performance, and carbon capture. This study proposed a novel control approach using bioflocculation boundaries for wasting control strategy to enhance effluent quality and stability while still meeting carbon capture goals. The bioflocculation boundaries were developed based on the oxygen uptake rate (OUR) ratio between contactor and stabilizer (feast/famine) in a high-rate contact stabilization (CS) system and this OUR ratio was used to manipulate the wasting setpoint. Increased oxidation of carbon or decreased wasting was applied when OUR ratio was <0.52 or >0.95 to overcome bioflocculation limitation and maintain effluent quality. When no bioflocculation limitations (OUR ratio within 0.52-0.95) were detected, carbon capture was maximized. The proposed control concept was shown for a fully automated OUR-based control system as well as for a simplified version based on direct waste flow control. For both cases, significant improvements in effluent suspended solids level and stability (<50-mg TSS/L), solids capture over the clarifier (>90%), and COD capture (median of 32%) were achieved. This study shows how one can overcome the process instability of current HRAS systems and provide a path to achieve more reliable outcomes. PRACTITIONER POINTS: Online bioflocculation boundaries (upper and lower limit) were defined by the OUR ratio between contactor and stabilizer (feast/famine). To maintain effluent quality, carbon oxidation was minimized when bioflocculation was not limited (0.52-0.95 OUR ratio) and increased otherwise. A fully automated control concept was piloted, also a more simplified semiautomated option was proposed. Wasting control strategies with bioflocculation boundaries improved effluent quality while meeting carbon capture goals. Bioflocculation boundaries are easily applied to current wasting control schemes applied to HRAS systems (i.e., MLSS, SRT, and OUR controls).

River direction prediction of Shuangliu District Fu River based on ArcSWAT model

The division and prediction of river basins provide important theoretical support for mountain torrents, flow direction control and governance. This paper takes Shuangliu District of Chengdu as the main research area. The experiment is supported by the elevation data of Fuhe River in Huanglongxi Town, Yong’an Town, Shuangliu District of Chengdu from 2020 to 2021. By constructing the model database, dividing the spatial unit of the basin and predicting the river trend, the arcswat model for the River Basin of Shuangliu District of Chengdu is established. The results show that the preliminary watershed area obtained by introducing elevation image analysis is the best. In the follow-up test, by combining the calculated results of hydrological system characteristics in the database with the weather data obtained from the world weather database, it better fitted the water conditions of Shuangliu area and showed excellent performance.

Design and Thermal Evaluation of Hybrid Split Solar Air Conditioner in Mosul/Iraq

In this paper, we conducted an experimental study to study the improvement of the coefficient of performance of a hybrid solar air conditioner and compare it with the performance of a conventional air conditioner. In addition to studying the rate of electrical energy savings for the hybrid system. The study included the study of the factors and variables affecting the performance of the hybrid solar air conditioner during three continuous months (June, July, and August). The hybrid solar air conditioner consisted of a conventional R-410a split air conditioner with cooling capacity (12,000 BTU) and a variable speed compressor integrated with a solar collector. The solar collector consists of a flat solar panel combined with a hot water storage tank. Inside the tank there is a copper coil heat exchanger, inside which the refrigerant leaving the compressor of the hybrid solar air conditioner passes. Two solenoid valves were installed to control the flow direction of the refrigerant leaving the compressor either to the solar heat exchanger and then to the condenser or directly to the condenser. The results showed that the highest improvement in the coefficient of performance of the hybrid solar air conditioner without refrigerant flow direction control - first case, and hybrid solar air conditioner with refrigerant flow direction control - second case are (12.2% and 16.3%) respectively compared to a conventional air conditioner, and that the highest rate of electrical energy savings for the solar hybrid air conditioner - the first and second cases are (15.9% and 18.7%) respectively compared to a conventional air conditioner.

Influence of guide vane profile on the flow energy dissipation in a reversible pump-turbine at pump mode

Pumped storage hydro (PSH) is a mature and widely used energy storage technique. The hydraulic dissipation of PSH will lead to the decline of power station efficiency. Therefore, it is important to find the reasons flow energy dissipation (FED). The adjustment of the flow channel will cause the change of flow energy dissipation. Guide vane is an important component of pump turbine, which has an influence on the problems of FED. In this paper, the FED in pump turbine with two guide vane profiles are analyzed. The combination of experimental method and numerical simulation method is adopted. Through experiments, the influence of two guide vane profiles on performance is clarified, and the method to judge the severity of Q-H instability is proposed. The FED under different working conditions were analyzed by entropy production. When the flow rate is at design point, the wake and local small flow separation causes FED. When the flow rate is large, FED is caused by the strong wake and flow separation in the runner. When the flow is small, the complex flow pattern in guide vane and back-flow cause high FED. The guide vane profiles have a great influence on FED. The match of blade leading edge and flow direction and flow control ability of guide vane affect the flow state caused the variation of FED.

Design and experiment of the components for soil flow direction control of hilling machine based on EDEM

Cultivation and hilling are important steps in crop field management and provide an important guarantee of crop quality and quantity. With the aim of addressing how the soil flow direction of a traditional cultivation and hilling machine is difficult to control, and because it is difficult to achieve high ridge soil cultivation, among other issues, the components of the soil flow direction control of a hilling machine was designed. The components of the soil flow direction control consisted of a soil-feeding plough device, spiral knives and guide cover devices, etc. The design and analysis of the guiding parts for the two tools of the soil-feeding plough device and the spiral knife were performed to obtain an appropriate guide wall and helix angle. The guiding principle in the flow direction control components was analyzed. The design of the guide wall adopts the torsional columnar plough surface, and the elementary line angle changes from stable to increasing. The analysis of spiral milling showed that when the spiral angle is large, the milling effect is better. According to the discrete element method, the working part of the machine-soil interaction model was established. EDEM software was used to simulate the control components for the soil flow direction of the hilling machine for compound cutting. The design method with a two-factor comprehensive test was used to study the linear velocity along the outer part of the spiral knife and the influence of the forward velocity of machine of the implement on the soil cultivation effect. The results of the discrete element simulation showed that both the linear velocity along the outer part of the spiral knife and the forward velocity of the machine have extremely significant effects on the transportation of particles to the ridge top and the hilling thickness. Following multiple comparisons of the average hilling thickness with different linear velocities along with the outer spiral knife and different forward velocities of the machine, it is concluded that the performance of the machine is better when the linear velocity along the outer spiral knife is 3.01 m/s and the forward velocity of the machine is 0.7 m/s. The research conclusion had great theoretical value and practical significance for the design of the machine, which worked for cultivation and hilling. Keywords: compound cutting, hilling machine, flow direction control, discrete element method, design DOI: 10.25165/j.ijabe.20221503.5857 Citation: Tong Z W, Li L H, Zhang X L, Chen Y, Liu X C, Zhou P L, et al. Design and experiment of the components for soil flow direction control of hilling machine based on EDEM. Int J Agric & Biol Eng, 2022; 15(3): 122–131.

Pumpless three-dimensional photo paper-based microfluidic analytical device for automatic detection of thioredoxin-1 using enzyme-linked immunosorbent assay.

Microfluidic-based biosensors have been developed for their precise automatic reaction control. However, these biosensors require external devices that are difficult to transport and use. To overcome this disadvantage, our group made an easy-to-use, cheap, and light pumpless three-dimensional photo paper-based microfluidic analytical device (3D-μPAD; weight: 1.5g). Unlike conventional paper-based microfluidic analytical devices, the 3D-μPAD can be used to control fluid flow in a 3D manner, thus allowing sophisticated multi-step reaction control. This device can control fluid flow speed and direction accurately using only the capillary-driven flow without an external device like a pump. The flow speed is controlled by the width of the microfluidic channel and its surface property. In addition, fluid speed control and 3D-bridge structure enable the control of fluid flow direction. Using these methods, multi-step enzyme-linked immunosorbent assay (ELISA) can be done automatically in sequence by injecting solutions (sample, washing, and enzyme's substrate) at the same time in the 3D-μPAD. All the steps can be performed in 14min, and data can be analyzed immediately. To test this device, thioredoxin-1 (Trx-1), a biomarker of breast cancer, is used as the target. In the 3D-μPAD, it can detect 0-200ng/mL of Trx-1, and the prepared 3D-μPAD Trx-1 sensor displays excellent selectivity. Moreover, by analyzing the concentration of Trx-1 in real patients and healthy individuals' blood serum samples using the 3D-μPAD, and comparing results to ELISA, it can be confirmed that the 3D-μPAD is a good tool for cancer diagnosis.

Fabrication of Ring-Shaped Deposits of Polystyrene Microparticles Driven by Thermocapillary Mechanism.

Fabrication of ring-shaped deposits of microparticles on solid surfaces with the desired length scales and morphology of particle arrangements is of great importance when developing modern optical and electronic resonators, chemical sensors, touch screens, field-emission displays, porous materials, and coatings with various functional properties. However, the controlled formation of ring-shaped patterns scaling from a few millimeters up to centimeters with simultaneous control of particle arrangement at the microscale is one of the most challenging problems in advanced materials science and technology. Here, we report a fabrication approach for ring-shaped structures of microparticles on a glass surface that relied on a local thermal impact produced by the subsurface heater and heat sink. Thermocapillary convection in the liquid covering microparticles in combination with evaporative lithography is responsible for the particle transport and the assembling into the ring-shaped patterns. An advantageous feature of this approach is based on the control of thermocapillary flow direction, achieved by changing the sign of the temperature gradient in the liquid, switching between heating and cooling modes. That allows for changing the particle transfer direction to create the ring-shaped deposits and dynamically tune their size and density distribution. We have studied the influence of the power applied to the heat source/sink and the duration of the applied thermal field on the rate of the ring fabrication, the sizes of the ring and the profile of the particle distribution in the ring. The proposed method is flexible to control simultaneously the centimeter scale and microscale processes of transfer and arrangements of particles and can be applied to the fabrication of ring structures of particles of different nature and shape.

Study on the relationship between the direction of air flow and the dust control effect in integrated excavation surface

In order to improve the dust control effect of integrated excavation surface, FLUENT was used to simulate the relationship between different inlet air flow direction and working face dust concentration distribution to study the relationship between inlet air flow direction and dust control effect of integrated excavation surface. In combination with field tests, the corresponding wall air duct was selected and processed and applied to engineering practice. The results show that different air distribution directions have different influence on the dust control effect of working face. When the Angle of radial air outlet is 0°, the air flow directly acts on the transport belt to form secondary pollution, and the dust control effect is not good. The best dust control effect is 15° or 30°.

Grid-Integrated SRM-Driven Solar Water Pump With Power Flow Management

This work presents a unidirectional power flow control for a solar-assisted water supply system with grid support. The solar photovoltaic (PV) array acts as a primary source whereas the grid is operated as a reserve supply to ensure an uninterruptable water supply irrespective of working conditions. The present system has a reduced payback period and an efficient solution of water pumping in the present energy scenario. An online dwell angle optimization technique with a fundamental switching operation of switched reluctance motor (SRM) drive is employed in this work. A second-ordered generalized integrator (SOGI)-based single directional power flow control is developed to achieve the required nature of grid parameters following the IEEE recommendations. Additionally, this controller also offers the PV array power optimization and voltage balancing across split dc-link capacitors at all situations. The developed system is tested for both volumetric and centrifugal pumps. A unique way of emulating the characteristic of the centrifugal pump using a dc generator and buck-boost converter is also discussed in this work. The authenticity of this system with developed unidirectional grid control is examined through both MATLAB-based simulation and experimental responses. Overall, the developed system provides a cost-effective, efficient, and maintenance-free PV array energized water pumping system with the grid support.

Single-Stage DAB-LLC Hybrid Bidirectional Converter With Tight Voltage Regulation Under DCX Operation

Working as a dc-dc transformer (DCX), which operates at the resonant frequency, is a suitable solution to achieve the maximum conversion efficiency of the LLC converter. However, because the fixed-frequency modulation is applied, the voltage regulation performance is limited. To achieve tight voltage regulation and fully utilize the advantages of LLC-DCX operation under bidirectional isolated power application, in this article, a single-stage dual active bridge (DAB) LLC hybrid bidirectional converter based on the sigma converter structure is proposed. In the proposed converter, the main power flows through the LLC converter, and DAB is used for the power flow direction control and output voltage regulation. In addition, a mathematical model of the proposed converter is derived for the controller design, which is verified by circuit simulation. Based on the model, the design of the controller and the circuit parameters are discussed with the goal of fast dynamics. Finally, the experimental results of a 1200-W prototype verify the effectiveness and advantages of the proposed topology and controller design.

Control of Jet Flow direction

Control of Jet Flow direction