Flow Control System Research Articles

Enhancing the High-lift Properties of a Supercritical Wing by Means of a Modulated Pulse Jet Actuator

In this experimental investigation, a pulse flow control system on a high-lift device of a wing with a NASA SC(2)-0714 airfoil within the Reynolds number range of the take-off and landing phases, is proposed. In this study, an innovative method of signal modulation has been used in order to simultaneously exploit the benefits of both low and high excitation frequencies in one actuator driving signal that are known to be effective in separation control. It is observed that the lift and drag coefficients are improved due to the use of modulated pulse jets compared to the simple pulse jet. Keywords: Flow Control, High-lift configuration, Pulsed jet, Burst modulation, aerodynamic efficiency

SEMICONDUCTOR THERMOELEMENTS FOR GAS FLOW CONTROL IN A CAULDRON

With the constant increase in energy prices, the cost of agricultural products increases, which reduces competitiveness in the domestic and foreign markets. In this regard, the development of energy-saving technologies and technical means becomes relevant. (Research purpose) The research purpose is increasing the efficiency of heat treatment of feed, reducing energy consumption by improving the energy supply system and automation of the gas cauldron. (Materials and methods) The article presents an energy-efficient cauldron for cooking feed in the personal farms of rural residents. An energy supply system for a cauldron with automatic regulation of gas flow in proportion to the heat flow consumed is described. The design feature of this scheme is the use of Peltier semiconductor elements forming a thermoelectric battery to manage gas flow. (Results and discussion) The article presents a design and technological scheme of an automated gas flow control system with a gas burner device, its composition and the operation principle. We have created a specific methodology for determining energy and mode parameters, an operating experimental sample of the energy supply system of a cauldron. Experimental studies were carried out to clarify the calculated energy and operating parameters, substantiate the nominal power of the gas burner device, and identify the advantages and disadvantages of a cauldron with new automation tools. The regularities of changes in gas flow, temperature, and voltage at the output of a thermoelectric battery have been described. Diagrams of changes in these parameters are presented. (Conclusions) The lowest energy costs for heating the contents of a 100-litres cooking cauldron to boiling are achieved when the boiler is equipped with a gas burner with a capacity of 14 kilowatts. Due to the use of an automated gas flow control system, energy savings of up to 20 percent are provided in proportion to the heat flow consumed.

Улучшение подъемных характеристик крыла со сверхкритическим профилем при использовании модулированного импульсного струйного актуатора

In this experimental investigation, a pulse flow control system on a high-lift device of a wing with a NASA SC(2)-0714 airfoil within the Reynolds number range of the take-off and landing phases, is proposed. In this study, an innovative method of signal modulation has been used in order to simultaneously exploit the benefits of both low and high excitation frequencies in one actuator driving signal that are known to be effective in separation control. It is observed that the lift and drag coefficients are improved due to the use of modulated pulse jets compared to the simple pulse jet.

Fluidic circuit board with modular sensor and valves enables stand-alone, tubeless microfluidic flow control in organs-on-chips.

Organs-on-chips are a unique class of microfluidic in vitro cell culture models, in which the in vivo tissue microenvironment is mimicked. Unfortunately, their widespread use is hampered by their operation complexity and incompatibility with end-user research settings. To address these issues, many commercial and non-commercial platforms have been developed for semi-automated culture of organs-on-chips. However, these organ-on-chip culture platforms each represent a closed ecosystem, with very little opportunity to interchange and integrate components from different platforms or to develop new ones. The translational organ-on-chip platform (TOP) is a multi-institutional effort to develop an open platform for automated organ-on-chip culture and integration of components from various developers. Central to TOP is the fluidic circuit board (FCB), a microfluidic plate with the form factor of a typical well plate. The FCB enables microfluidic control of multiple components like sensors or organ-on-chip devices through an interface based on openly available standards. Here, we report an FCB to integrate commercial and in-house developed components forming a stand-alone flow control system for organs-on-chips. The control system is able to achieve constant and pulsatile flow recirculation through a connected organ-on-chip device. We demonstrate that this system is able to automatically perfuse a heart-on-chip device containing co-cultures of cardiac tissues derived from human pluripotent stem cell-derived cardiomyocytes and monolayers of endothelial cells for five days. Altogether, we conclude that open technology platforms allow the integration of components from different sources to form functional and fit-for-purpose organ-on-chip systems. We anticipate that open platforms will play a central role in catalyzing and maturing further technological development of organ-on-chip culture systems.

Control of series impedance of power lines using power flow controller

In this paper, the possibility of unified power flow controller (UPFC) to modulate both series resistance R and series reactance X of an overhead power line is discussed. The classical power flow control system of the UFPC is modified in the manner that standard input references signals (active and reactive powers) are replaced by reference signals of series resistance and reactance. Using the procedure described in this work, the reference signals for active and reactive powers are generated indirectly. The operation of UPFC in proposed operation mode is analyzed using computer simulation, based on a model of single machine infinite bus (SMIB) with constant impedance loads and two parallel lines. The goal is to show that UPFC is capable to control both series line parameters (R and X) directly and independently by means of a simple control system without additional decoupling controllers. An additional task is to show that power flows can be indirectly controlled this way. The step response of series line resistance and reactance is used to validate the operation of the proposed control system. The obtained results clearly show that all goals are fulfilled.

Fuzzy modelling and control of project cash flows

An analysis of the scientific literature on project cash flow control and fuzzy modelling shows that project cash flows are modelled using only basic approaches drawn from fuzzy theory, which may distort the credibility of the model. In this paper, we therefore propose to use the whole spectrum of fuzzy arithmetic, and to select operations that suit the nature of the cash flows in question, their dependencies and the preferences of the project manager. An analysis of the literature also shows that in practically all existing models of project costs and cash flow management, project costs and cash flows are treated at a very high level of generality (without considering the various types of project, factors influencing their variability and signals warning of imminent cash-related problems), and estimations are not updated on an ongoing basis throughout the duration of the project. The results of a survey performed with the participation of 100 project managers show that this simplistic view of project cash flows may be distorting, and cannot guarantee the development of an efficient project cost and cash flow control system. We propose an approach that at least partially compensates for these drawbacks: it differentiates between types of project cash flows and the factors and triggers affecting changes in cash flows. Two case studies are used for a an initial verification of the approach. The paper concludes with suggestions for further research perspectives.

Research of functioning processes of wireless sensor networks

The article is devoted to the research of problems of optimal control of data flow routing in heterogeneous sensor networks of variable topology under conditions of constraints and uncertainties. To solve the problem of synthesis of optimal data transmission routes in sensor networks, it is necessary to synthesize a graph model, formally define the optimization problem, investigate the processes of functioning of network elements and obtain formalized descriptions of the dependence of network elements. The mathematical model of functioning of the distributed system of intelligent data flow control in sensor networks of variable topology is considered based on the formal model of the functioning of the distributed system of intelligent network management, the properties of the processes of optimal load management of nodes and the data network as a whole are investigated. The results of the research allowed to obtain formal descriptions of the dependence of the load of the computing system of the sensor network on the time of the data transmission process, waiting time, service time on the load of the computing system of the sensor network, to determine quantitative indicators of delay and loss of data packets depending on the functioning modes.

MODEL OF INTELLECTUAL PEDESTRIAN FLOW MANAGEMENT SYSTEM

This scientific article proposes a model of pedestrian and car flow control system that can characterize the operation of two different control modes, the first of which is fully automatic, and the second works in automated mode, the results of which depend on information about the current situation on the road. the number of pedestrians and cars or depends on the intensity of traffic. In order to demonstrate the work of the proposed model, we will take some sections of the direct road where there is an adjustable pedestrian crossing. The system can determine the number of pedestrians in two ways: through surveillance cameras and with available statistics, such as information about the intensity at specific times. The second method, namely the application of pre-known parameters such as the intensity of pedestrian and traffic flows is used when it is impossible to determine the current situation on the road due to some reasons such as accident, bad weather and so on. The modes will be switched using the functionwhich will determine the mode of regulation of traffic lights according to the time intervals at which the intensity of the flows will also change. The automatic control system will work during rush hour, when the city's transport network operates. the greatest load. The second mode is for certain periods of time when the intensity of pedestrian flow is low, for example at night. The relationship between these intensity and time will be established statistically. The mode of automatic or "hard" regulation determines the duration of the pedestrian and car phases of traffic lights depending on the number of pedestrians and cars. If it is impossible to determine the number of road users using video cameras, then we calculate due to the intensity of traffic flows, and the automated control mode, ie "call" calculates the duration of the delay between two calls and the duration of the pedestrian phase. crowds and traffic near regulated pedestrian crossings.

Boundary layer state detection using piezoelectric sensors

Two piezoelectric series bimorph sensors were embedded below the skin of a NACA 0012 symmetrical airfoil to detect the local state of the boundary layer during wind tunnel testing. Small vanes piercing the airfoil skin were glued onto the bimorphs providing a mechanical coupling to the local mechanical force fluctuations imparted by the local unsteady boundary layer flow. The state of the boundary layer at the sensor sites was varied by changing the angle of attack. The objective of this work was to establish the ability of this sensor concept to accurately distinguish among typical boundary layer states such as attached laminar flow, turbulent flow and separated flow. The output of the sensor was compared to concurrent time-resolved particle image velocimetry measurements, which served as a validation technique. Using the developed sensor response envelope, a single data point time series of the piezo electrical signal was proven to be sufficient to accurately detect the boundary layer state on classical airfoils in the low Reynolds number regime. In projected future applications, single or arrays of bimorph sensors can be used to map the boundary layer of more complex or morphing shape airfoils. The fast response of the sensor can in principle be utilised in closed-loop flow control systems, aimed at drag reduction or lift enhancement.

Performance Analysis of Hybrid Multi-Port AC-DC/DC-DC Embedded Based Energy Flow Optimizing Using Resilient Power Flow Control (RPFC) Technique

In recent decades, the utilization of renewable power sources has proven to be a reliable and clean vitality more universal, and with specific ultimate goals to achieve efficient and renewable energy power generation. The proposed system is improve the stabilize energy flow between micro grids and the main grid. The power generation of the each and every renewable sources are monitored and controlled by the proposed Resilient Power Flow Control (RPFC) system and also the energy flow variation of the grid system is analyzed and presented in this paper. This work demonstrates the role of energy routers in optimizing the efficient and flexible way of energy stabilization in grid system. This analysis model establishes the entire system, including power routers, interconnected microcircuits, and the main grid. Interconnected microcircuits were analyzed by various controller facilitated by power routers, and corresponding control strategies were developed. The proposed system shows the effectiveness and reliability of the control strategy for micro-grid interconnection and flexible energy flow correspondence.

An Automated Aerosol Collection and Extraction System to Characterize Electronic Cigarette Aerosols.

Electronic cigarette (e-cigarette) market increased by 122% during 2014–2020 and is expected to continue growing rapidly. Despite their popularity, e-cigarettes are known to emit dangerous levels of toxic compounds (e.g., carbonyls), but a lack of accurate and efficient testing methods is hindering the characterization of e-cigarette aerosols emitted by a wide variety of e-cigarette devices, e-liquids, and use patterns. The aim of this study is to fill this gap by developing an automated E-cigarette Aerosol Collection and Extraction System (E-ACES) consisting of a vaping machine and a collection/extraction system. The puffing system was designed to mimic e-cigarette use patterns (i.e., power output and puff topography) by means of a variable power-supply and a flow control system. The sampling system collects e-cigarette aerosols using a combination of glass wool and a continuously wetted denuder. After the collection stage, the system is automatically washed with absorbing and extracting liquids (e.g., methanol, an acetaldehyde-DNPH solution). The entire system is controlled by a computer. E-ACES performance was evaluated against conventional methods during measurements of nicotine and carbonyl emissions from a tank type e-cigarette. Nicotine levels measured using glass fiber filters and E-ACES were not significantly different: 201.2 ± 6.2 and 212.5 ± 17 μg/puff (p = 0.377), respectively. Differences in formaldehyde and acetaldehyde levels between filter-DNPH cartridges and the E-ACES were 14% (p = 0.057) and 13% (p = 0.380), respectively. The E-ACES showed reproducible nicotine and carbonyl testing results for the selected e-cigarette vaping conditions.

Review of enhanced power quality using unified power flow control system in electrical network

Flexible FACTS system of AC transmission. FACTS Devices can regulate electricity flow, develop the transmission capacity for power management. UPFC is a multipurpose fact controller carried on design of the constant voltage source. As an electrical device UPFC for rapid reactive power adjustment on high voltage electricity transport grid. Unified power flow control (UPFC). The latest FACTS gadget is UPFC. This combines series and shunting compensator characteristics and enables Power reactive and response to be controlled. UPFC utilization reduces difficulties in power quality including voltage sink and voltage surge. This article addresses UPFC and also several novel topologies for FACTS controllers.

Data-driven enhancement of coherent structure-based models for predicting instantaneous wall turbulence

Predictions of the spatial representation of instantaneous wall-bounded flows, via coherent structure-based models, are highly sensitive to the geometry of the representative structures employed by them. In this study, we propose a methodology to extract the three-dimensional (3-D) geometry of the statistically significant eddies from multi-point wall-turbulence datasets, for direct implementation into these models to improve their predictions. The methodology is employed here for reconstructing a 3-D statistical picture of the inertial wall coherent turbulence for all canonical wall-bounded flows, across a decade of friction Reynolds number (Reτ). These structures are responsible for the Reτ-dependence of the skin-friction drag and also facilitate the inner-outer interactions, making them key targets of structure-based models. The empirical analysis brings out the geometric self-similarity of the large-scale wall-coherent motions and also suggests the hairpin packet as the representative flow structure for all wall-bounded flows, thereby aligning with the framework on which the attached eddy model (AEM) is based. The same framework is extended here to also model the very-large-scaled motions, with a consideration of their differences in internal versus external flows. Implementation of the empirically-obtained geometric scalings for these large structures into the AEM is shown to enhance the instantaneous flow predictions for all three velocity components. Finally, an active flow control system driven by the same geometric scalings is conceptualized, towards favourably altering the influence of the wall coherent motions on the skin-friction drag.

Techno economic analysis of microgrid with an efficient energy management system and inverter control strategies

A microgrid comprises of distributed energy resources with the capability of operating independently as an islanded mode or in a grid connected mode. The efficacy of a microgrid is based on the performance of the control strategy and the energy management strategy. Therefore, in this paper the feasibility of an efficient inverter control strategy and energy management strategy for microgrid are studied. The proposed microgridis implemented with master-slave energy management control and battery management system for effective power flow control in an islanded and grid connected mode. A three-layer hierarchical energy management strategy comprising of master-slave system to provide continuous supply at all conditions and effective switchover operations between grid connected and islanded modes of operation is proposed. The voltage-frequency control under standalone mode of operation and P-Q control using hysteresis current control under grid-connected mode of operation are developed and the system parameters like real power, reactive power and voltage at the PCC are analyzed after the implementation of proposed controllers under islanded and grid connected modes of operation. The proposed model achieves voltage and frequency regulation under varying system operating conditions. Also, a techno-economic analysis is performed in HOMER software where the cost of energy and return on investment are studied for the proposed microgrid system by which levelized cost and payback period is reduced. The proposed control algorithms are implemented through MATLAB simulation and tested in a real-time for 1 kW grid-connected solar PV system.

Fiber optic pressure measurement on a complex outer winglet model with active flow control actuators

The next generation of aircraft requires novel approaches on lift increase and drag reduction technologies as active flow control to counter local flow separations. Testing and monitoring its effectiveness in flight require precise pressure evaluation as a possible control input. Pressure-based measurements of local flow separation are challenging utilizing conventional electrical pressure sensors. These sensors might show degradation of their long-term performance in harsh environments, e. g., in real aircraft applications, due to their low overload protection, susceptibility to electromagnetic influences, and corrosion. Fiber optic measurements overcome those challenges and promise to be a robust sensing solution. We investigate the potential application of a novel fiber optic measurement system that monitors the active flow control system's effectiveness. Furthermore, the results are compared to conventional static pressure measurements. Due to the high-frequency capabilities of the fiber optic sensors, the dynamic behavior of the boundary layer separation and vortex generation was captured in the frequency domain. An industry-relevant outer wing was equipped with 25 fiber optic pressure sensors positioned at one wingspan section for this experiment. The experiments were conducted at a Reynolds number Re=1.1⋅106and a Mach number Ma=0.12. Wind tunnel testing results show that fiber optic pressure sensors can measure aerodynamic characteristics and, furthermore, even allow a detailed look at the dynamic behavior.

Field evaluations of a deep learning-based intelligent spraying robot with flow control for pear orchards

This study proposes a deep learning-based real-time variable flow control system using the segmentation of fruit trees in a pear orchard. The real-time flow rate control, undesired pressure fluctuation and theoretical modeling may differ from those in the real world. Therefore, two types of preliminary experiments were conducted to examine the linear relationship of the flow rate modeling. Through preliminary experiments, the parameters of the pulse width modulation (PWM) controller were optimized, and a field experiment was conducted to confirm the performance of the variable flow rate control system. The field test was conducted for three cases: all open, on/off control, and variable flow rate control, showing results of 56.15 ( $$\pm 17.24$$ )%, 68.95 ( $$\pm 21.12)$$ % and 57.33 ( $$\pm 21.73$$ )% for each control. The result revealed that the proposed system performed satisfactorily, showing that pesticide use and the risk of pesticide exposure could be reduced.

Flow Characteristics and Novel Applications of Synthetic Jets: A Review

Abstract Synthetic jets, often abbreviated as “SJs” or “Synjets,” are a type of zero net mass flux (ZNMF) jets, which have gained popularity due to their ability to transfer momentum without transferring mass. This property distinguishes SJs from their counterpart traditional continuous jets. Over a stretch of time, SJs have been employed extensively in applications such as active flow control, impingement heat transfer, and miniature electronics cooling. However, researchers are now slowly extending the frontiers of SJ research and making efforts to utilize excellent properties of SJs in novel applications such as autonomous underwater vehicles (AUVs), marine systems, and bio-inspired propulsion systems. This paper strives to identify the gaps in the current research and the areas that have remained unexplored yet. The article begins with a brief discussion of the origin of SJs, i.e., “acoustic streaming.” Resulting segments talk about the formation criteria and the recent works employing various configurations of orifices and cavities. The paper discusses the critical concepts such as jet impact factor, volumetric efficiency, and propulsive efficiency of synthetic jets. It is followed by introduction of novel flow control systems employing SJs such as gurney flaps, bumps, and electro-active synthetic jets. Finally, the most innovative applications of SJs such as AUVs, unmanned air vehicles, and jetting cavities are also brought out. Pulsatile jet flows found in jellyfish, cephalopod, squid, and salp have been discussed in great detail. The exhaustive discussion on future prospects strives to not only provide the reader with the comprehensive insights into SJs, but also to motivate future researchers to overcome the gaps identified in this paper.

PERFORMANCE STUDIES ON WATER FLOW CONTROL USING P, PI AND PID CONTROLLERS

The main purpose of this study is to revitalize the concept of wise and controlled supply of water for domestic, industrial and agricultural applications which facilitate sustainable usage of fresh water resources. As Eritrea is striving to manage its water resources, attention paid primarily to enable water flow control mechanisms in municipal water distribution systems. A table top process control trainer (PCT) was tested through proportional(P), integral (I) and derivative (D) control mechanisms using Ziegler-Nichols second method to evaluate the tuning variables. Applying exclusively P control action, critical period of oscillation (𝑃𝑃𝑐𝑐𝑐𝑐) was estimated as 1.4 sec at proportional band value of 9. P, PI and PID controller performance studies were conducted with tuned variables on the water flow control system at different step disturbances between 20 – 50 % and their corresponding responses were characterized. P controller exhibited faster responses with consistent increments in offset, PI controller recorded highest overshoot values with negligible offset and prolonged settling times. PID controller showed less overshoot values and faster response times than PI but it increased chatter on the control output signal. The study revealed that the system can be safely controlled between 0-80 LPH. If the offset is not a major concern, P controller would be reflected suitable with simple design and minimum expenditure, else PI controller makes offset to zero though it possesses higher settling times. In other words, PID controller is complex using more tuning parameters, need expensive maintenance, and has resulted an intermittent noise in the output signal.

Design and Implementation of Low-Cost Field Crop Sprayer Electronic Flow Control System

The purpose of this research is to present the designs required and methodology of prototype production to control electronically a mechanical-controllable system on a case study. The system under consideration is a field crop sprayer. The reason for the investigation of this system is operator exposure to the harmful chemical and inefficiency of flow control. It is necessary to precisely start and end the chemical flow at the requested location, to close a certain part of the spraying line, and to prevent overdosing during the pulverization. An Arduino system was designed to control a precise electronic flow system. In this regard, Mechanical flow-control valves are equipped with 16 bar pressure-resistant and chemical resistant solenoid valves. Designs were produced and prototypes were presented. Low-cost sprayer control systems (SCS) chemical losses were reduced by 6% to 20%. The ergonomic design increased the productivity of the operator. Moreover, this system reduced fuel consumption by 2% to 6%. It is 40% more economical than existing systems. As a result, productive electronic control was achieved in the field crop sprayer.

CFD Analysis of the Optimization of Length of Capillary Tube for a Vapor Compression Refrigeration System

Abstract: The capillary tube is commonly employed in refrigerant flow control systems. As a result, the capillary tube's performance is optimal for good refrigerant flow. Many scholars concluded performance utilising experimental, theoretical, and analysis-based methods. This paper examines the flow analysis of a refrigerant within a capillary tube under adiabatic flow circumstances. For a given mass flow rate, the suggested model can predict flow characteristics in adiabatic capillary tubes. In the current work, R-134a refrigerant has been replaced by R600a refrigerant as a working fluid inside the capillary tube, and the capillary tube design has been modified by altering length and diameter, which were obtained from reputable literature. The analysis is carried out using the ANSYS CFX 16.2 software. The results show thatutilising a small diameter and a long length (R600a refrigerant flow) is superior to the present helical capillary tube. The most appropriate helical coiled design with a diameter of 0.8 mm and a length of 3 m is proposed. Keywords: Capillary Tube, Condenser, Refrigeration effect, CFD.