scholarly journals Fluidized Bed Jet Milling Process Optimized for Mass and Particle Size with a Fuzzy Logic Approach

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3303 ◽  
Author(s):  
Jaroslaw Krzywanski ◽  
Dariusz Urbaniak ◽  
Henryk Otwinowski ◽  
Tomasz Wylecial ◽  
Marcin Sosnowski
Keyword(s):  
Fuzzy Logic ◽  
Fluidized Bed ◽  
Rotational Speed ◽  
Milling Process ◽  
Operating Conditions ◽  
Air Pressure ◽  
Practical Significance ◽  
Wide Range ◽  
The Mean ◽  
Jet Milling

The milling process is a complex phenomenon dependent on various technological and material parameters. The development of a fluidized bed jet milling model is of high practical significance, since milling is utilized in many industries, and its complexity is still not sufficiently recognized. Therefore, this research aims to optimize fluidized bed jet milling with the use of fuzzy logic (FL) based approach as one of the primary artificial intelligence (AI) methods. The developed fuzzy logic model (FLMill) of the investigated process allows it to be described as a non-iterative procedure, over a wide range of operating conditions. Working air pressure, rotational speed of the classifier rotor, and time of conducting the test are considered as inputs, while mass and mean Sauter diameter of the product are defined as outputs. Several triangular and constant linguistic terms are used in the developed FLMill model, which was validated against the experimental data. The optimum working air pressure and the test’s conducting time are 500 kPa and 3000 s, respectively. The optimum rotational speed of the classifier is equal to 50 s−1, considering the mass of the grinding product, and 250 s−1 for the mean Sauter diameter of the product. Such operating parameters allow obtaining 243.3 g of grinding product with the mean Sauter diameter of 11 µm. The research proved that the use of fuzzy logic modeling as a computer-based technique of solving mechanical engineering problems allows effective optimization of the fluidized bed jet milling process.

Measurement of Unsteady Flow in Pump-Turbine for Hydropower Using PIV Method

2009 ◽  
Author(s):  
Nobuhiko Fukuda ◽  
Satoshi Someya ◽  
Koji Okamoto
Keyword(s):  
Rotational Speed ◽  
Velocity Measurement ◽  
Numerical Procedure ◽  
Hydraulic Turbine ◽  
Operating Conditions ◽  
High Time ◽  
Pump Turbine ◽  
Guide Vanes ◽  
Runner Blade ◽  
Wide Range

It is thought that the pressure fluctuation can occur due to the interaction between flow through guide vanes and flow into runner blades, resulting in a vibration of turbine and a blade cracking, in a hydraulic turbine operated in a wide range for flexible power demand. High accurate velocity measurement with high time/spatial resolution can help to clarify the mechanism of the interaction and to provide good experimental data for the validation of numerical procedure. So the aim of present study is to estimate the unstable velocity field quantitatively in the area between guide vanes and runner blades, using high time-resolved particle image velocimetry (PIV). Two types of velocity measurements were carried out, i.e., phase-locked measurement and high time sequential velocity measurement, in a pump-turbine model with 20 guide vanes and 6 runner blades. The characteristic of the flow field varied corresponding to the operating conditions such as flow rate and rotational speed. Opening angles of guide vanes were kept uniform. A clockwise vortex was generated at inside of the runner blade under smaller rotational speed. A counterclockwise vortex was separated at the backside of the runner blade under higher rotational speed. At any operating conditions, the velocity between guide vanes and runner blades oscillated periodically at the blade passing frequency.

Simulation And Analysis of An Intelligent Power System Stabilizer Using Fuzzy Logic

2020 ◽  
Vol 27 (4) ◽  
pp. 70-86
Author(s):  
firas AlDurze ◽  
sura Abdullah
Keyword(s):  
Fuzzy Logic ◽  
Power System ◽  
Synchronous Machine ◽  
Operating Conditions ◽  
Superior Performance ◽  
Power System Stabilizer ◽  
Operation Conditions ◽  
Wide Range ◽  
Simulation Results ◽  
System Stabilizer

The basic aim of the power system stabilizer is to damp the fluctuations that occur on the rotating axis of the synchronous generator that result from noise or disturbance on the power system. This is achieved by producing an appropriate damping torque for these fluctuations across the excitation circuit of the generator and for a wide range of operation conditions. The study describes the types of power system stabilizers and giving an mathematical model of the power system that consists of a synchronous machine connected to the infinite bus though transmission lines. This has been achieved by simulating the electric and mechanical equations of power systems and proposing a methodological approach to design a Fuzzy Logic Power System Stabilize (FPSS) relaying in the design on the (Matlab/Fuzzy logic toolbox).Speed deviation (Δω) and acceleration (∆ώ) of the synchronous machine are chosen as the input signals to the fuzzy controller in order to achieve a good dynamic performance .The complete range for the variation of each of the two controller inputs is represented by a 7×7 decision table, i.e. 49 rules using proportional derivative like fuzzy logic. The power system (SMIB) was tested with the presence and absence of the excitation system, then (CPSS) was added, and then (FPSS).The simulation results of the proposed fuzzy logic on )SMIB( gave a better dynamic response, decreased the settling time and good performance of the stabilizer in damping the fluctuations that arise in the speed of rotation of the generator and its active power in various operating conditions when proposed (FPSS) is compared with conventional PSS. The simulation results proved the superior performance of the proposed (FPSS).

Flow of Damp Powder in a Rotating Impervious Cone

2010 ◽  
Vol 78 (2) ◽  
Author(s):  
Arnaud F. M. Bizard ◽  
Digby D. Symons ◽  
Norman A. Fleck ◽  
David Durban
Keyword(s):  
Differential Equation ◽  
Axisymmetric Flow ◽  
Central Zone ◽  
Operating Conditions ◽  
Order Ordinary Differential Equation ◽  
Spherical Coordinate ◽  
Explicit Analytical Solution ◽  
Wide Range ◽  
Governing Differential Equation ◽  
The Mean

A one dimensional analytical model is developed for the steady state, axisymmetric flow of damp powder within a rotating impervious cone. The powder spins with the cone but migrates up the wall of the cone (along a generator) under centrifugal force. The powder is treated as incompressible and Newtonian viscous, while the shear traction at the interface is taken to be both velocity and pressure dependent. A nonlinear second order ordinary differential equation is established for the mean through-thickness velocity as a function of radius in a spherical coordinate system, and the dominant nondimensional groups are identified. For a wide range of geometries, material parameters, and operating conditions, a midzone exists wherein the flow is insensitive to the choice of inlet and outlet boundary conditions. Within this central zone, the governing differential equation reduces to an algebraic equation with an explicit analytical solution. Furthermore, the bulk viscosity of the damp powder does not enter this solution. Consequently, it is suggested that the rotating impervious cone is a useful geometry to measure the interfacial friction law for the flow of a damp powder past an impervious wall.

Attrition Behavior of Coal Ash Under Circulating Fluidized Bed Combustion Conditions

2003 ◽  
Author(s):  
Franz Winter ◽  
Xin Liu
Keyword(s):  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Coal Ash ◽  
Operating Conditions ◽  
Laboratory Scale ◽  
Silica Sand ◽  
Electrical Heating ◽  
Fluidized Bed Combustion ◽  
Bed Temperature ◽  
Wide Range

The attrition behavior of ash produced from two bituminous and one anthracite coal was studied under laboratory-scale circulating fluidized bed combustor (CFBC) conditions. After the ash was produced in the oven, the ash sample with a size range from 0.1 to 1 mm was fed into the hot CFBC, which was heated by electrical heating shells and fluidized by air. The laboratory-scale CFBC was operated with using fine silica sand (40 to 80 μm) as bed material. After a certain time the operation was stopped, all particles were collected and sieving analysis was performed to obtain the actual particle size distribution (PSD) of the coal ash. The operating conditions were changed in a wide range, i.e. the bed temperature from 600 to 850°C, the fluidizing velocity from 1.2 to 2 m/s, the residence time from 60 to 120 min and the design of the cyclone. The effects of operating conditions and coal type were studied and their relative importance is discussed. Elemental analysis of the coal ashes showed that Si and Ca may play an important role during attrition.

scholarly journals Heat Transfer Performance in a Superheater of an Industrial CFBC Using Fuzzy Logic-Based Methods

Entropy ◽  
2019 ◽  
Vol 21 (10) ◽  
pp. 919 ◽  
Author(s):  
Krzywanski
Keyword(s):  
Heat Transfer ◽  
Fuzzy Logic ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Practical Significance ◽  
Overall Heat Transfer Coefficient ◽  
Bed Temperature ◽  
The Heat Transfer Coefficient

The heat transfer coefficient in the combustion chamber of industrial circulating flidized bed (CFB) boilers depends on many parameters as it is a result of multifactorial mechanisms proceeding in the furnace. Therefore, the development of an effective modeling tool, which allows for predicting the heat transfer coefficient is interesting as well as a timely subject, of high practical significance. The present paper deals with an innovative application of fuzzy logic-based (FL) method for the prediction of a heat transfer coefficient for superheaters of fluidized-bed boilers, especially circulating fluidized-bed combustors (CFBC). The approach deals with the modeling of heat transfer for the Omega Superheater, incorporated into the reaction chamber of an industrial 670 t/h CFBC. The height above the grid, bed temperature and voidage and temperature, gas velocity, and the boiler’s load constitute inputs. The developed Fuzzy Logic Heat (FLHeat) model predicts the local overall heat transfer coefficient of the Omega Superheater. The model is in good agreement with the measured data. The highest overall heat transfer coefficient is equal 220 W/(m2K) and can be achieved by the SH I superheater for the following inputs l = 20 m, tb = 900 °C, v = 0.95, u = 7 m/s, M-C-R = 100%. The proposed technique is an effective strategy and an option for other procedures of heat transfer coefficient evaluation.

Study on the Mean Value of Particle Concentration Signal in Silicon Power Fluidized Bed

2012 ◽  
Vol 550-553 ◽  
pp. 2936-2940
Author(s):  
Xing Yong Liu ◽  
Hu Yang ◽  
You Cheng Wang ◽  
Zhuo Xu Deng
Keyword(s):  
Neural Network ◽  
Fluidized Bed ◽  
Particle Concentration ◽  
Rbf Neural Network ◽  
Radial Distance ◽  
Mean Value ◽  
Operating Conditions ◽  
Axial Distance ◽  
The Mean ◽  
Concentration Signal

The particle concentration signals of silicon powder in the fluidizing gas i.e. air under different operating conditions were determined. The diameter of silicon particles, operating velocity, radial distance and axial distance are used as input vector; the mean value of particle concentration signal in the silicon power fluidized bed is used as a target vector. The RBF neural network is applied to build the predicted model of the mean value in silicon power fluidized bed. The result shows that the prediction of mean value through the RBF neural network is prior to that by BP neural network, and its error is less than 0.2%.

Numerical and experimental study on knocking combustion in turbocharged direct-injection engines for a wide range of operating conditions

2021 ◽  
pp. 146808742110601
Author(s):  
Magnus Kircher ◽  
Emmeram Meindl ◽  
Christian Hasse
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
Numerical Study ◽  
Direct Injection ◽  
Operating Conditions ◽  
Auto Ignition ◽  
Spark Timing ◽  
Crank Angle ◽  
Wide Range ◽  
The Mean

A combined experimental and numerical study is conducted on knocking combustion in turbocharged direct-injection spark-ignition engines. The experimental study is based on parameter variations in the intake-manifold temperature and pressure, as well as the air-fuel equivalence ratio. The transition between knocking and non-knocking operating conditions is studied by conducting a spark timing sweep for each operating parameter. By correlating combustion and global knock quantities, the global knock trends of the mean cycles are identified. Further insight is gained by a detailed analysis based on single cycles. The extensive experimental data is then used as an input to support numerical investigations. Based on 0D knock modeling, the global knock trends are investigated for all operation points. Taking into consideration the influence of nitric oxide on auto-ignition significantly improves the knock model prediction. Additionally, the origin of the observed cyclic variability of knock is investigated. The crank angle at knock onset in 1000 consecutive single cycles is determined using a multi-cycle 0D knock simulation based on detailed single-cycle experimental data. The overall trend is captured well by the simulation, while fluctuations are underpredicted. As one potential reason for the remaining differences of the 0D model predictions local phenomena are investigated. Therefore, 3D CFD simulations of selected operating points are performed to explore local inhomogeneities in the mixture fraction and temperature. The previously developed generalized Knock Integral Method (gKIM), which considers the detailed kinetics and turbulence-chemistry interaction of an ignition progress variable, is improved and applied. The determined influence of spark timing on the mean crank angle at knock onset agrees well with experimental data. In addition, spatially resolved information on the expected position of auto-ignition is analyzed to investigate causes of knocking combustion.

Computational Study of the Unsteady Flow Structure of the Buoyancy-Driven Rotating Cavity With Axial Throughflow of Cooling Air

2009 ◽  
Author(s):  
Zain Dweik ◽  
Roger Briley ◽  
Timothy Swafford ◽  
Barry Hunt
Keyword(s):  
Flow Structure ◽  
Rotational Speed ◽  
Operating Conditions ◽  
Structure Evolution ◽  
High Rotational Speed ◽  
Wide Range ◽  
Recirculation Zones ◽  
Cooling Air ◽  
The Impact ◽  
Engine Power

Buoyancy driven flows such as the one that occurs in the inter-disk space of an axial compressor spool plays a major role in determining the gas turbine engine projected life and performance. Details of the developed flow structure inside these spaces largely impact the operating temperatures on the rotating walls of the compressor hardware and therefore impact the life of the machine. In this paper the impact of engine power condition (Idle, Highpower, and Shutdown) on the flow structure for these rotating cavities is studied under a wide range of operating conditions encountered by realistic turbomachines. A computational analysis is performed using commercially available computational tools for grid generation (ICEM-CFD) and turbulent-flow simulation (CFX). A computational test case was developed to imitate the rig-test conditions of Owen and Powell, and computed results were assessed and validated by comparison with their experimental results. A total of fifteen unsteady CFD cases covering a wide range of operating conditions (Rossby Number Ro, Rotational Rayleigh Number Raφ, and axial Reynolds Number Rez) were analyzed. The computed flow results revealed that the flow structure evolution, starting from a steady state solution, is such that radial arms of different number (according to the engine power condition), surrounded by a co-rotating (cyclonic) and counter-rotating (anti-cyclonic) pair of vortices, start to form at different locations. Cold air from the central jet enters the cavity in these arms under the combined action of the centrifugal buoyancy and the Coriolis forces. As time proceeds, the flow structure tends to become virtually invariant with time in a repeatable pattern. The number of radial arms, strength of recirculation zones, and the degree of invasion of the central cooling air toward the shroud are all dependent on the engine power condition. The computations also revealed that at high rotational speed the flow stabilizes, and the unsteady features of the flow structure (cyclonic and anti-cyclonic recirculation zones surrounding the radial arms, radial invasion of the cooling air in the radial arms, and its final impingement upon the shroud surface) eventually disappear after a threshold value of the rotational speed is reached.

Prediction of Ingress Through Turbine Rim Seals: Part 2—Combined Ingress

2010 ◽  
Author(s):  
J. Michael Owen ◽  
Oliver Pountney ◽  
Gary Lock
Keyword(s):  
Experimental Data ◽  
Rotational Speed ◽  
Numerical Solutions ◽  
External Flow ◽  
Operating Conditions ◽  
Flow Rates ◽  
Wide Range ◽  
Experimental Values ◽  
The One ◽  
Empirical Constants

In Part1 of this two-part paper, the orifice equations were solved for the case of externally-induced ingress, where the effects of rotational speed are negligible. In Part 2, the equations are solved, analytically and numerically, for combined ingress (CI) where the effects of both rotational speed and external flow are significant. For the CI case, the orifice model requires the calculation of three empirical constants, including Cd,e,RI and Cd,e,EI, the discharge coefficients for rotationally-induced (RI) and externally-induced (EI) ingress. For the analytical solutions, the external distribution of pressure is approximated by a linear saw-tooth model; for the numerical solutions, a fit to the measured pressures is used. It is shown that, although the values of the empirical constants depend on the shape of the pressure distribution used in the model, the theoretical variation of Cw,min (the minimum nondimensional sealing flow rate needed to prevent ingress) depends principally on the magnitude of the peak-to-trough pressure difference in the external annulus. The solutions of the orifice model for Cw,min are compared with published measurements, which were made over a wide range of rotational speeds and external flow rates. As predicted by the model, the experimental values of Cw,min could be collapsed onto a single curve, which connects the asymptotes for RI and EI ingress at the respective smaller and larger external flow rates. At the smaller flow rates, the experimental data exhibit a minimum value of Cw,min, which undershoots the RI asymptote. Using an empirical correlation for Cd,e, the model is able to predict this undershoot, albeit smaller in magnitude than the one exhibited by the experimental data. The limit of the EI asymptote is quantified, and it is suggested how the orifice model could be used to extrapolate effectiveness data obtained from an experimental rig to engine-operating conditions.

scholarly journals Design of PI Fuzzy Logic Gain Scheduling Load Frequency Control in Two-Area Power Systems

Designs ◽  
2019 ◽  
Vol 3 (2) ◽  
pp. 26 ◽  
Author(s):  
Tawfiq Hussein ◽  
Awad Shamekh
Keyword(s):  
Fuzzy Logic ◽  
Power Systems ◽  
Frequency Control ◽  
Gain Scheduling ◽  
Operating Conditions ◽  
Load Frequency Control ◽  
Control Technique ◽  
Load Frequency ◽  
Wide Range ◽  
Fuzzy Logic Technique

In this paper the use of the proportional integral (PI) algorithm incorporated with the fuzzy logic technique has been proposed as advanced gain scheduling load frequency control (GLFC) in two-area power systems. The proposed controller comprises two-level control systems, such that it consists of a pure integral compensator which is connected in parallel with a PI controller. However, and based on load demand, the PI parameters are updated online by means of fuzzy logic rules. With this control technique it becomes possible to eliminate steady state errors as well as to maintain good transient responses. The task of keeping a stable and overall satisfactory mode of operation in interconnected electric power systems is the main goal of any control strategy. This should be guaranteed over a wide range of operating conditions and particularly in sudden and drastic load changes. Therefore, the suggested approach has been examined following abnormal changes in loading conditions to clarify its reliability. The report also investigates the performance of the pure integral (I) controller and GLFC in individual configurations to highlight the advantages of the offered algorithm over the standard ones. The criterion of integral square error (ISE) has been exploited in the performance assessment for the designed controllers. Several simulation scenarios have been conducted, using the MATLAB–Simulink package, to illustrate the proficiency of the developed technique.

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