Optimal Flow Distribution Research Articles

Research on flow distribution optimization method of fluid loop system based on generalized Lagrange multiplier method

Abstract With the development of space science in China, the scale of space application payloads continues to increase, and the demand for heat dissipation is also gradually increasing. The fluid loop thermal control is a more efficient way of heat dissipation. In order to optimize the heat dissipation effect of the fluid loop system, this paper establishes a thermal model of the fluid loop system and converts it into a constrained optimization problem. The generalized Lagrange multiplier method is used to calculate the optimal flow distribution strategy, and the influence of the weight is analyzed, which provides a reference for the setting of the weight in practical applications.

Optimization of container traffic distribution on the railway network

The paper considers the problem of optimal redistribution of transit container flows on the railway network. The problem is proposed to be solved as the problem of a multi-commodity flow of minimum cost using the relaxation method. The relaxation method allows choosing the most efficient variant of the next solution at each iteration step. To search for the optimal distribution of container flows on the network, graph theory was used, i.e., the network is presented as a multigraph with a set of vertices and arcs, for which the costs of transporting a unit of production, the maximum and minimum values of the flows between the vertices are given, the conditions for maintaining the flow at the vertices of the graph and restrictions on the amount of flow along the arcs are given. It has been established that in order to implement the task, it is necessary to take into account the unit costs for the movement of container flows between the nodes of the railway network, taking into account the capacity of the branches between the junction stations. The developed mathematical model for the redistribution of container traffic allows you to identify areas with limited throughput, develop options for optimization measures, and, as a result, achieve an economic effect by reducing the cost of transporting containerized cargo.

Pumping Station Design in Water Distribution Networks Considering the Optimal Flow Distribution between Sources and Capital and Operating Costs

The investment and operating costs of pumping stations in drinking water distribution networks are some of the highest public costs in urban sectors. Generally, these systems are designed based on extreme scenarios. However, in periods of normal operation, extra energy is produced, thereby generating excess costs. To avoid this problem, this work presents a new methodology for the design of pumping stations. The proposed technique is based on the use of a setpoint curve to optimize the operating and investment costs of a station simultaneously. According to this purpose, a novel mathematical optimization model is developed. The solution output by the model includes the selection of the pumps, the dimensions of pipelines, and the optimal flow distribution among all water sources for a given network. To demonstrate the advantages of using this technique, a case study network is presented. A pseudo-genetic algorithm (PGA) is implemented to resolve the optimization model. Finally, the obtained results show that it is possible to determine the full design and operating conditions required to achieve the lowest cost in a multiple pump station network.

IMPROVING THE METHOD OF DETERMINING THE VALUE OF WATER LEVELS IN VERTICAL WELLS OF GROUP WATER COLLECTION

Purpose. Reconstruction of water supply systems to meet the increased water needs of consumers is a complex, time-consuming and expensive task. Reconstruction options include expanding existing water intakes or building new ones anywhere in the existing water supply network. The variety of options is accompanied by changes in water consumption in the sections of the networks and, importantly, in the flow distribution. The introduction of additional sources into the existing water supply systems requires a detailed study of the factors affecting the technical characteristics of the systems and responsible for the economic component of the project. Methodology. The influence of the determining factors on the total head losses in the water distribution network during the reconstruction of the water supply system is analyzed. An algorithm for finding the optimal network points for connecting an additional power source is proposed, which includes determining the optimal flow distribution and the corresponding technical changes for each selected option; total capacity of pumping stations and heads; analysis of the complete set of the water supply system of the accepted options; an economic analysis of the construction investment and operating costs that will accompany the operation of the water supply system design options. Findings. The choice of the optimal connection points for additional power sources depends on the amount of water flow in the network sections and the flow distribution. It is shown that the nodes of the end sections of the network most correspond to the conditions for searching for optimal points and can be fed from different directions, depending on the amount of additional flow. With an additional water flow rate no more than two nodal flow rates, the total head losses in the network sections are minimal. When an additional flow rate of more than two nodal flows enters the final node, an increase in head losses is observed, which can have critical values depending on its increase. The introduction of additional water flows into the network, which exceed two nodal ones, requires the use of intermediate network nodes located at sections with a higher throughput as connection points. Originality. The analysis of the factors influencing the choice of points of connection of additional power sources of the water supply network during its expansion is carried out. The analysis of the points was carried out with limited ranges of the values of water consumption of additional feeding − less and equal to the nodal ones, two and three times larger than the nodal ones. The ways of finding the optimal option for choosing a network node as a point of connection of additional power are shown. Practical value. The use of the analysis results will make it possible to most effectively search for the optimal variant of reconstruction of water supply systems, take into account the influence of determining factors on the characteristics of networks with changes in water consumption and flow distribution. The use of the analysis results will make it possible to most effectively search for the optimal variant of reconstruction of water supply systems, take into account the influence of determining factors on the characteristics of networks with changes in water consumption and flow distribution.

Optimization of Multi-Quality Water Networks: Can Simple Optimization Heuristics Compete with Nonlinear Solvers?

Optimal management of water systems tends to be very complex, especially when water quality aspects are included. This paper addresses the management of multi-quality water networks over a fixed time horizon. The problem is formulated as an optimization program that minimizes cost by determining the optimal flow distribution that satisfies the water quantity and quality requirement in the demand nodes. The resulted model is nonlinear and non-convex due to bilinear terms in the mass balance equations of blending multi-quality flow. This results in several local optima, making the process of solving large-scale problems to global optimality very challenging. One classical approach to deal with this challenge is to use a multi-start procedure in which off-the-shelf local optimization solvers are initialized with several random initial points. Then the final optimal solution is considered as the lowest objective value over the different runs. This will lead to a cumbersome and slow solution process for large-scale problems. In light of the above, this study supports using ultra-fast simple optimization heuristics, which despite their moderate accuracy, can still reach the optimum solution when run many times using a multi-start procedure. As such, the final solution from simple optimization heuristics can compete with off-the-shelf nonlinear solvers in terms of accuracy and efficiency. The paper presents a simple optimization heuristic, which is specially tailored for the problem and compares its performance with a state-of-the-art nonlinear solver on large-scale systems.

Development of a systematic approach and mathematical support for the evacuation process

In modern conditions, due to the vastness of the territory of Kazakhstan, with a certain probability, natural disasters such as earthquakes, floods, avalanches, as well as accidents, destruction of buildings, epidemics, release of chemical toxic substances at industrial enterprises, fires in educational and medical institutions are possible, which justifies the relevance of modern methods and technologies for solving the problem of evacuation. The peculiarity of this work lies in the formation of an integrated approach for organizing the evacuation process both in peacetime as training for the event of an emergency situation (emergency), and in the event of the emergency itself. A conceptual diagram of an evacuation system is proposed that uses heterogeneous sources for receiving and transmitting information about the onset of an emergency. The input and output sources for receiving and transmitting information about the number of people in the building are determined. The main purpose of the system is to form an operational real-time evacuation plan. This work is the result of a phased implementation of an integrated evacuation system, which consists in building a mathematical model and a method for solving the problem of maximum flow in the network. A mathematical model has been developed for the optimal flow distribution along the Grindshiels network with the analysis of the flow formation and the characteristics of people’s motion in enclosed spaces. A game-theoretic approach and mathematical methods of the theory of hydraulic networks for finding an equilibrium state in flow-distribution networks have been developed. An algorithm for solving the evacuation problem using the graph approach is proposed. The results of this paper make it possible to systematically organize training evacuations, prepare resources, train the personnel responsible for evacuation in order to quickly respond in an emergency and carry out the evacuation process in order to avoid major consequences.

Optimizing Data Intensive Flows for Networks on Chips

A novel framework is proposed to find efficient data intensive flow distributions on Networks on Chip (NoC). Voronoi diagram techniques are used to divide a NoC array of homogeneous processors and links into clusters. A new mathematical tool, named the flow matrix, is proposed to find the optimal flow distribution for individual clusters. Individual flow distributions on clusters are reconciled to be more evenly distributed. This leads to an efficient makespan and a significant savings in the number of cores actually used. The approach here is described in terms of a mesh interconnection but is suitable for other interconnection topologies.

Modeling of the Complex Ventilation Network Related to Livezeni Mine

Abstract In order to ensure the microclimate conditions for the exploitation of useful mineral substances underground, it is necessary to ensure the control of gas emissions from the field and from the exploited space. For this it is necessary to ensure a balanced air flow at the level of each active mining work in order to dilute the gases. Specialized programs are used to ensure the optimal distribution of air flows at the level of each mining work. The paper presents the modelling and solving of the ventilation network related to Livezeni Mine with the help of the 3D CANVENT program.

변속기 이중 주축에서 오일 홀 위치 및 형상에 따른 유량 분배 설계기술

변속기 이중 주축에서 오일 홀 위치 및 형상에 따른 유량 분배 설계기술

3D printed manifolds for improved flow management in electrodialysis operation for desalination

Desalination with electrodialysis requires cell designs for optimal flow distribution. Such units include polymeric frames, electrodes, membranes and spacers. Frames are used for mechanical support of electrodes and hydraulic connectors. Their geometry needs to be customized for appropriate fluid management and hydraulic compartmentalization. Typically, such electrodialysis frames are manufactured by drilling solid plastic blocks. However, design flexibility is required to fit the increasing number of developments incorporating new materials and flow inter-connectivity. Here we propose additive manufacturing coupled with computational design to optimize flow dynamics and their coupling with physical devices. First, CAD models are proposed to incorporate major improvements in process lines, and to integrate internal manifold cavities. Even fluid flow and pressure drop distributions are verified by numerical models at given flowrates. The frames were 3D printed and assembled with electrodes and membranes to investigate their performance, and to experimentally confirm numerical predictions. Compared to conventional frames, and as a result of the even distribution of the fluids inside the cell, it was possible to reach an improved (21% higher) limiting current density while ensuring pH stability. Finally, our approach can be integrated in new designs, taking advantage of material selection and geometrical complexity of 3D-printing to add novel functionalities.

Coordinating Electric Vehicle Flow Distribution and Charger Allocation by Joint Optimization

A two-stage stochastic programming model is established to minimize EV's expected total journey time under stochastic traffic conditions, by jointly optimizing the allocation of chargers and the distribution of EV flows. Based on sample average approximation, a feasible deterministic equivalent of the original stochastic problem is obtained. Then, a hybrid solution method, composing of a Tabu-based search and sequential quadratic programming (SQP), is proposed. The Tabu heuristic manages the charger allocation problem, where each solution candidate undergoes a second-stage EV flow optimization. SQP is applied to optimally distribute the EV flows, which is proved to be a convex problem. Extensive simulations are carried out using the eastern Massachusetts highway network. Results show that the proposed algorithm outperforms existing approaches by finding high-quality charger allocation and optimal flow distribution policies under different traffic conditions. Additionally, the two-stage model designates charging resource sufficiency by statistically estimating a lower bound for the number of chargers to allocate, which in practice helps to prevent over-investment on charging resources.

Application of autoregressive dynamic adaptive (ARDA) model in real-time wind power forecasting

Wind prediction technology has been the focus on the national research with the basis of the power system planning, a reference for power dispatch, and the optimal power flow distribution. Prediction technology is moving into the direction of controlling refinement with the development of the information technology, the artificial intelligence technology, and the improvement of edge computing devices. The wind farms can use real-time wind power prediction to improve their overall efficiency through advanced planning of the wind turbine adjustment and the pre-setting of the yaw, pitch, and generation excitation control systems. This paper proposes an innovative autoregressive dynamic adaptive (ARDA) model based on the improvement of the autoregressive (AR) model. The fixed parameter estimation method of the AR model is improved in the proposed model to a dynamically adaptive stepwise parameter estimation method. Meanwhile, the coefficients of the model are updated adaptively based on the characteristics of wind power data, which improves the accuracy of the proposed model. The prediction accuracy of the proposed model is further improved by the residual function. It was observed that the model adapts well to wind power data with different degrees of volatility. The ARDA model and two other models were tested by using stationary and fluctuating wind power data (unit: seconds), and the wind power prediction results at different forecasting step lengths were compared. It was observed that the ARDA model is more accurate, with faster calculation rate, and better dynamic adaptability to data fluctuations than the ARIMA and LSTM models. This paper proposes an important method for real-time power prediction that can be employed for the advanced control and improved the power generation of wind farms.

Multimodal Freight Transportation Based on Multicriteria Optimization by Time Indicators

A multicriteria approach with temporal indicators in optimizing the distribution of cargo flows in multimodal transport and technological system is presented. Based on the infrastructure indicators of the considered part of the railway landfill and the economic and geographical volumes of cargo accumulation, a mathematical model of the transport process is developed, expressed as a nonlinear integer programming problem. For various combinations of several objective functions, which are temporary indicators of the transportation process, an algorithm of optimal distribution of cargo flows for the considered loading stations and unloading stations is developed. Computational procedures for finding the Pareto optimal distribution of cargo flows are implemented in the environment of a computer mathematics system, which can be Free Ware. The distribution of grain cargo flows, which, as well known, are especially relevant from a commercial point of view for Russian exports, was chosen as a specific object for implementing the developed optimization approach.

Mathematical model of optimal distribution of freight flows in the region in the transport network and their development

Mathematical model of optimal distribution of freight flows in the region in the transport network and their development

Heuristic methods for minimal controller location set problem in transportation networks

To be used efficiently, transportation networks require control strategies to optimize flow distribution. However, the location and type of controllers employed in a transportation network directly impact the level of performance reachable by traffic control policies. In order to guarantee that the highest level of performance is reachable, fully exploiting the available network capacity and reducing negative externalities, we explore methods to identify relevant controller locations in transportation networks while minimizing the number of controllers used. Previous work provided an exact approach to identify controller locations on complex networks. However, said approach exhibits complications when applied to transportation networks containing bi-directional links. We therefore propose simple heuristic algorithms relying only on topological information to solve this problem, while also avoiding heavy computation, thus being able to determine a solution to the minimal controller location set problem on large networks. Based on the existing framework, we aim to provide an experimental setup, with diverse network sizes and configurations to analyze the performances of different heuristic methods, in order to develop an efficient algorithm.

Minimizing the Effects of On-Chip Hotspots Using Multi-Objective Optimization of Flow Distribution in Water-Cooled Parallel Microchannel Heatsinks

Abstract The industry shift to multicore microprocessor architecture will likely cause higher temperature nonuniformity on chip surfaces, exacerbating the problem of chip reliability and lifespan. While advanced cooling technologies like two phase embedded cooling exist, the technological risks of such solutions make conventional cooling technologies more desirable. One such solution is remote cooling with heatsinks with sequential conduction resistance from chip to module. The objective of this work is to numerically demonstrate a novel concept to remotely cool chips with hotspots and maximize chip temperature uniformity using an optimized flow distribution under constrained geometric parameters for the heatsink. The optimally distributed flow conditions presented here are intended to maximize the heat transfer from a nonuniform chip power map by actively directing flow to a hotspot region. The hotspot-targeted parallel microchannel liquid cooling design is evaluated against a baseline uniform flow conventional liquid cooling design for the industry pressure drop limit of approximately 20 kPa. For an average steady-state heat flux of 145 W/cm2 on core areas (hotspots) and 18 W/cm2 on the remaining chip area (background), the chip temperature uniformity is improved by 10%. Moreover, the heatsink design has improved chip temperature uniformity without a need for any additional system level complexity, which also reduces reliability risks.

APPLICATION OF PASSENGER FLOW ANALYSIS METHODS TO RESTRUCTURING THE PASSENGER TRANSPORT SYSTEM OF THE LEVOBEREZHNY DISTRICT OF MOSCOW

One of the key problems when ensuring the quality of life of residents of large cities of the world is to raise the transport services standards. Among the main aspects of solving this problem is the search for the optimal distribution of flows of personal and ground public municipal passenger transport. In this regard the planning, design, and localization of multifunctional transport interchange hubs (hereinafter – TIH) take on great significance. The experience of their arrangement has received wide acceptance in many countries of the world. In recent years Moscow has also been actively working on the design and construction of TIH; large-scale projects of transport infrastructure facilities construction are being developed. The TIH system should be capable of flexible response to changing transport needs of the population and to their realistic transformation to effectively ensure transport mobility of the population.The objective of the study is to test the passenger flow analysis methods and their application for simulation of the organization and planning of the transport interchange hub in a large district of the city, planning of the route network of municipal passenger transport.The route network of suburban and intercity transport of Northern Administrative District of Moscow has been reviewed. The passenger traffic within the TIHs Rechnoy vokzal and Khovrino has been analyzed.Based on the study, the authors propose to change the route network of ground urban passenger transport. The implementation of route network changing proposals can shorten the time spent on passenger travel and transfer. It is the authors’ opinion that the developed route network is more effective than the existing one and meets the design standards and requirements approved by local city regulations.

Physiological and Biochemical Rationale of Yogasana

Yogic exercises have been known to increase mental and physical control of the body. Earlier practices ofyogasan and pranayam have revealed physical and mental well being. Yoga has great therapeutic potentialin management of related diseases stress. It improves the psyche of the individual because training causingdecrease in psychic stimuli to vasomotor and respiratory centre hence there is less increase in sympatheticactivity and less decrease in parasympathetic activity with an optimal blood flow distribution. Greateramount of fat is utilized for providing energy sparing glycogen.

Research of Thyristor Voltage Regulator Effect on Power Flows Control in Distribution Electric Networks

The article is devoted to the power flows redistribution process research in distribution electric networks (DEN) with thyristor voltage regulator (TVR). TVR is intended to regulate power flows and voltage stabilization in the medium-voltage network of 6-20 kV. The problems in the medium-voltage network of 6-20 kV were analyzed and solutions were determined. It was established that the key development trend of DEN is the engineering and adoption of devices based on D-FACTS technologies. In addition, we considered the features, technical characteristics and control system of TVR. The research of power flow distribution in electric system was based on a simulation model of DEN with TVR. TVR allows to regulate power flows by changing the amplitude and phase angle of the voltage, with the help of longitudinal-transverse regulation. The results have shown that the TVR allows to align load schedules, to stabilize the voltage level in complex networks with unevenly loaded nodes and to realize optimal distribution of power flows in the electrical network.

Short-Term Optimal Operation of Baluchaung II Hydropower Plant in Myanmar

The short-term optimal operation model discussed in this paper uses the 2016 to 2018 daily and monthly data of Baluchaung II hydropower station to optimize power generation by minimizing water consumption effectively in order to get more revenue from optimal operation. In the first stage, run-off-river type Baluchaung II hydropower station data was applied in a mathematical model of equal micro-increment rate method for optimal hydropower generation flow distribution unit results. In the second stage, dynamic programming was used to get optimal hydropower generation unit distribution results. The resultant data indicated that optimized results can effectively guide the actual operation run of this power station. The purpose of the optimal load dispatching unit was to consider the optimal power of each unit for financial profit and numerical programming on the actual data of Baluchaung II hydropower plant to confirm that our methods are able to find good optimal solutions which satisfy the objective values of 17.75% in flow distribution units and 24.16% in load distribution units.