Abstract: This paper reports a numerical study on the extinction limits and flame structures of opposed-jet syngas diffusion flames. A narrowband radiation model is coupled to the OPPDIF program, which uses detailed chemical kinetics and thermal and transport properties to enable the study of 1-D counterflow syngas diffusion flames over the entire range of flammable strain rates with flame radiation. The effects of syngas composition, strain rate, ambient pressure, and dilution gases on the flame structures and extinction limits of H2/CO synthetic mixture flames were examined. Results indicate the flame structures and flame extinction are impacted by the composition of syngas mixture significantly. From hydrogen-lean syngas to hydrogen-rich syngas fuels, flame temperature increases with increasing hydrogen content and ambient pressure, but the flame thickness is decreased with ambient pressure and strain rates. Besides, the dilution effects from CO2, N2, and H2O, which may be present in the syngas mixtures, were studied. The flame is thinner and flame temperature is lower when CO2 is the diluents instead of N2. The combustible range of strain rates is extended with increasing hydrogen percentage and ambient pressure, but it is decreased the most with CO2 as the dilution gas due to the dilution effects. Complete flammability limits using strain rates, maximum flame temperature as coordinates can provide a fundamental understanding of syngas combustion and applications.
Abstract: Registration of 3D point clouds is one of the most fundamental phases during the process of reverse engineering and most challenging at the same time. This phase consists on matching two or more different point clouds into one data set in order to have them share the same global coordinate system. In this paper we present a new approach for automatic registration of 3D point clouds that uses the genetic algorithm (GA) as a global optimization method. We introduce a trips extraction technique for rough registration, which extracts important geometric information from a point cloud. Another contribution in this paper is the introduction of the Interpenetration Fraction Measure (IFM), which maximizes the number of points that overlap two different point clouds. The algorithm we present also takes advantage of the parallel computing power of today’s multi-core processors, and other techniques for further efficiency. Finally, we present some experimental data with comparisons for analysis and further discussion about the algorithm’s performance.
Abstract: In many parts of the world, row crops are treated with herbicides. Because of environmental concerns, crop cultivation is suggested as an excellent method of weed control. The object of this study was to design and construct a high speed inter-row cultivator. The speed of plowing has a significant effect not only on the depth of plowing but on factors which affect the quality of soil preparation such as loosening of the upper soil layer, cutting roots of the previous crops, covering and plowing in of weeds, leveling the finished surface of the field, displacement of the son layer and so on. In this study, the designed and constructed cultivator has a toolbar, unit frame, disk coulter and a flat sweep. The unit frame is attached to a tractor mounted tool bar by a suspension linkage. The suspension linkage allows the unit frame to move up and down relative to a tool bar that the cultivator unit is attached to. The numerical analysis was performed with COSMOS/M 1.71 FEM software (Structural Research and Analysis Corporation, CA).
Abstract: Turbo lag and low starting torque is the challenges of turbochargers. These challenges can be met with the implementation of an additional boosting device which can significantly boost the starting torque of the engine. the goal of this study is to show how the steady-state performance of a turbocharged SI engine can be improved by supercharging turbocharged engine. A one dimensional model for a turbocharged V type, four cylinder CNG engine has been developed and studied in detail using GT-POWER software. For validation purposes the model results are compared with experimental data available where acceptable results with good accuracy has been observed.
Abstract: The most common form of energy recycling system is Combined Heat and Power (CHP) plants. The CHP plant is a complex system and still under intensive development by many researchers. The system needs to be developed in quick and efficient manners with low resources based on modeling and simulation method. With the development of CHP library in open source Modelica language, it could be used as a base for further advancement of CHP technology. The aim of this work is to design a structure of initial version of a model library for the dynamic simulation of Combined Heat and Power plants (CHP). Modular approach and top-down design have been implemented in the model library development. A solid base for this work is defined which includes rules in modeling the components (e.g. robustness and reusability), default library structure arrangement and model documentation. By strictly follow the rules and concepts introduced in this work, the mistakes in modeling is minimized. The designed library in Modelica language will provide an organized environment in modeling a CHP plant.
Abstract: This paper presents a novel approach to control a 3-RRR (revolute-revolute-revolute) planar parallel manipulator applying an active force control (AFC) strategy. A PID-based computed torque controller (CTC) was first designed and developed to demonstrate the basic and stable response of the manipulator in order to follow a prescribed trajectory. Then, the AFC part was incorporated into the control scheme in series with the CTC (AFC-CTC) in a cascade form. Performance of the system was demonstrated by the computer simulation results. By using the AFC method, the design of trajectory tracking controller can be conducted based on a precise model of the system. The overall tracking performance was improved with using AFC scheme in presence of known or unknown disturbances. Results clearly illustrate the robustness and effectiveness of the proposed AFC-based scheme as a robust disturbance rejecter compared to the conventional CT controller.
Abstract: This paper describes an experiment on Electric Power Steering (EPS) system of a car. Nowadays EPS system can be considered as a Mechatronics system that reduces the amount of steering effort by directly applying the output of an electric motor to the steering system. In this paper, the constitutions, operational mechanism and control strategies of EPS system are introduced. A potentiometer measures driver input to the steering wheel, both direction and rate of turn. This information is fed into a microcontroller that determines the desired control signals to the motor to produce the necessary torque needed to assist. Although an electro hydraulic power assisted steering system can be used to reduce the fuel consumption, but the maximum benefit can be obtained if electronic system is applied instead of the hydraulic mechanism. The paper shows that a good power steering control technique is achieved by designing a Mechatronics system. The experimental results for the designed EPS system are also analyzed in this paper.
Abstract: This paper presents the design and prototype of an electromechanical actuator with some constraints that allow creating a feasible prototype with reasonably accuracy. Also, was consider the variation of friction forces due to changes in load conditions to obtain the mathematical relation between the maximum load, the required motor torque and the maximum angular acceleration of the payload; important parameters that contribute to determine the suitable motor.
Abstract: This paper presents a method for solving the station-keeping problem of near-space airship (NSA) at an altitude of 22km above sea level with wind influence. Firstly, according to the system overall configuration, the nonlinear mathematical model of NSA is established. Secondly, considering the steady wind and turbulence influences, the station-keeping control law of NSA longitudinal plane which divided into forward control loop and vertical control loop is designed. The vertical position control loop adopts the dual PID control method. In order to improve attitude response performance and decrease energy consumption of actuators, attitude control allocation strategy between fins and vectored thruster is provided. At last, the simulation experiment proves the validity of the proposed station-keeping control method of NSA.
Abstract: A new design of a wind water heater (WWH) is presented. In this new system, the wind energy is directly converted to thermal energy used to heat the water. The wind energy is converted to frictional thermal energy by dissipation within a thin layer of oil. The oil is filled in an annular gap confined between two horizontal concentric cylinders with different diameters; the outer insulating cylinder is rotating while the inner cylinder is fixed. The heat generated is transferred into the inner cylinder then to the heat exchanger. The heat transfer fluid is carrying the heat from the heat exchanger to the water storage tank by mechanical pump. A mathematical model is proposed to model the system mechanical and thermal behavior. The theoretical model has been solved analytically to estimate the amount of thermal energy generated by the system based on a given wind design speed at the site. The theoretical performance of the proposed heater is analyzed and the effects of different design parameters on the heater performance are investigated. The theoretical predictions of the system performance show that the efficiency of proposed wind water heater at design wind speed is equal to 34.8%. The relatively low conversion efficiency of kinetic wind energy to sensible thermal one is due to the limitation imposed by the windmill performance.