Comparative Study of Electric Machines for Stirling Generator Application

2021 ◽  
Vol 43 ◽  
pp. 73-92
Author(s):  
Victor Zogbochi ◽  
Patrice Chetangny ◽  
Jacques Aredjodoun ◽  
Didier Chamagne ◽  
Gerald Barbier ◽  
...  
Keyword(s):  
High Efficiency ◽  
Acoustic Noise ◽  
Complex Problem ◽  
Rotating Machines ◽  
Step Method ◽  
Minimum Requirement ◽  
Torque Density ◽  
Performance Space ◽  
Space Saving ◽  
Electromagnetic Models

The choice of a machine for an application and a given specification remains a complex problem. This will involve, for example, bringing together criteria such as: performance, space saving, economical, reliable, little acoustic noise and others. The best machine selection to fulfill all constraints is an important step for the project to be realized. This work focus on Stirling Engine based Generator and study all types of rotating machines that can be employed for maximum electric power production. Analytical electromagnetic models where developed for all types of rotating machines that satisfied minimum requirement for the project by solving Maxwell equations. The purpose is to develop the design model and combine electromagnetic and thermal study of the machines. Finite Element Method is used to compare the performances of the generators for the best choice. Results show that for applications not requiring bigger output power, the major criteria for the selection is the optimal magnetic induction created by the inducer in the stationary part of the machine. For application such as Stirling generators, permanent magnet (PM) machine satisfy many comparison criteria such as maximum power at low speed, torque density, high efficiency. Beyond exposing a selection method for a project, this work lay down a step-by-step method for engineers and scientists for the crucial stage of design and conception work

scholarly journals NUMERICAL THERMAL MODEL OF AN INCANDESCENT LAMP FOR SATELLITES TESTING

2020 ◽  
pp. 50-58
Author(s):  
Dmitriy Kulikov ◽  
Keyword(s):  
Mathematical Modeling ◽  
Thermal Model ◽  
High Efficiency ◽  
Complex Problem ◽  
Thermal Design ◽  
Halogen Lamp ◽  
Quality Model ◽  
Good Convergence ◽  
The Monte Carlo Method ◽  
Model Generator

In the present article the author gives the results work to create a numerical thermal model of infrared (IR) emitter on the base of tubular halogen lamp (THL) KGT-220-1300, as one of the elements of the equipment used when conducting thermal vacuum tests (TVT) of satellites. As a tool to solve complex problem of heat transfer used software Thermal Model Generator. Variants of calculations for the operation of the lamp at different voltages are carried out. The results of mathematical modeling using band approximation of the properties of the system elements in combination with the Monte Carlo method in solving the problem of heat exchange by radiation showed high efficiency. The performed analysis of the correctness of the results showed good convergence with the data of previous experiments on measuring the temperature of the quartz bulb, which confirms the reliability of the results. Getting a high-quality model of this type at the disposal of satellite thermal engineer is an important step in the complex work aimed at conducting end-to-end mathematical modeling of satellite thermal design, and will also solve a number of issues related to the methodological support of TVT, their implementation and optimization.

The Gear Bearing Drive: A Novel Compact Actuator for Robotic Joints

2013 ◽  
Author(s):  
Elias Brassitos ◽  
Constantinos Mavroidis ◽  
Brian Weinberg
Keyword(s):  
High Speed ◽  
High Efficiency ◽  
Low Cost ◽  
Planetary Gear ◽  
Mechanical Efficiency ◽  
Torsional Stiffness ◽  
Maximum Output ◽  
Torque Density ◽  
Robotic Joints ◽  
Advanced Robotics

Advanced robotics requires a new generation of actuators able to exhibit a number of desirable characteristics ranging from high power density and high efficiency, high positioning resolution, high torque capacity and torsional stiffness, lightweight designs and low-cost packages. In this paper, we present the development and the experimental evaluation of a new actuator, aimed at improving the torque density and mechanical efficiency of actuated robotic joints, and enhancing the portability and effectiveness of robotic systems engaged in biomechanical applications such as rehabilitation robots and wearable exoskeletons. The new actuator, called the Gear Bearing Drive (GBD), consists of a two-stage planetary gear arrangement coupled through the planets and driven by an external rotor brushless motor that is inscribed within the input stage sun gear. This planetary configuration enables for incredible high-speed reductions and allows for embedding the motor directly within the gearbox saving significant space on the actuator length. Our initial experimental prototypes have demonstrated impressive performance with the potential to deliver more than 30Nm of continuous torque with 85% mechanical efficiency and 0.0005 degree of backlash, and up to 200 rpm maximum output speed in a highly compact and robust package.

scholarly journals In situ stiffness manipulation using elegant curved origami

2020 ◽  
Vol 6 (47) ◽  
pp. eabe2000
Author(s):  
Zirui Zhai ◽  
Yong Wang ◽  
Ken Lin ◽  
Lingling Wu ◽  
Hanqing Jiang
Keyword(s):  
High Power ◽  
High Efficiency ◽  
Negative Stiffness ◽  
Positive Zero ◽  
Uniform Load ◽  
Saving Energy ◽  
Space Saving ◽  
Force Transmissibility ◽  
New Applications

The capability of stiffness manipulation for materials and structures is essential for tuning motion, saving energy, and delivering high power. However, high-efficiency in situ stiffness manipulation has not yet been successfully achieved despite many studies from different perspectives. Here, curved origami patterns were designed to accomplish in situ stiffness manipulation covering positive, zero, and negative stiffness by activating predefined creases on one curved origami pattern. This elegant design enables in situ stiffness switching in lightweight and space-saving applications, as demonstrated through three robotic-related components. Under a uniform load, the curved origami can provide universal gripping, controlled force transmissibility, and multistage stiffness response. This work illustrates an unexplored and unprecedented capability of curved origami, which opens new applications in robotics for this particular family of origami patterns.

Torque Optimization of Double-Stator Switched Reluctance Machine

2013 ◽  
Vol 313-314 ◽  
pp. 45-50 ◽  
Author(s):  
Mohammadali Abbasian ◽  
Vahid Hanaeinejad
Keyword(s):  
Finite Element ◽  
Acoustic Noise ◽  
Optimization Method ◽  
Torque Ripple ◽  
Radial Force ◽  
Switched Reluctance Machine ◽  
Switched Reluctance ◽  
Torque Density ◽  
Reluctance Machine ◽  
Switched Reluctance Machines

Double-stator switched reluctance machines benefit from a high torque density and a low radial force level in comparison with conventional switched reluctance machines resulting in a lower vibration and acoustic noise. Therefore, they are suitable candidate for automotive applications. However, torque pulsation which is also a source for vibration is still remained and should be alleviate by dimension optimization of the machine. This paper presents a design optimization of a double-stator switched reluctance machine for improving the magnetic torque quality of the machine. For this purpose finite element method along with response surface methodology is used to optimize three parameters of the machine to maximize torque quality factor i.e. the average torque to torque ripple ratio in the machine. Genetic algorithm method is also employed as an optimization tool. The aim of optimization is to maximize the ratio of average torque to torque ripple. Finite element results are presented to verify the optimization method.

On Study of High Speed Permanent Magnet Synchronous Motor without Iron Core

2013 ◽  
Vol 706-708 ◽  
pp. 882-887
Author(s):  
Ji Zhu Liu ◽  
Yang Jun Wang ◽  
Tao Chen ◽  
Ming Qiang Pan ◽  
Li Guo Chen ◽  
...  
Keyword(s):  
Permanent Magnet ◽  
High Speed ◽  
High Efficiency ◽  
Permanent Magnet Synchronous Motor ◽  
Synchronous Motor ◽  
Iron Core ◽  
Torque Density ◽  
Optimized Model ◽  
Low Efficiency ◽  
Design And Manufacture

Iron loss will be rapidly increased when the permanent magnet iron core synchronous motor runs at a high speed, which makes the motor produce so much heat that causes low efficiency of the motor and even burns out the motor. The iron-core-free permanent magnet synchronous motor remedies this defect and has a high efficiency at high speed. This article makes a comparative analysis on the iron-core-free permanent magnet synchronous motor torque density with different slot engagement classifications. The paper puts forward an optimized model of permanent magnet synchronous motor without the iron core. The technology of the permanent magnet synchronous motor without iron core is studied based on this model which provides a method to design and manufacture the iron-core-free permanent magnet synchronous motor.

A Detailed Study of the Interaction Between Two Rows of Cooling Holes

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Y. Jiang ◽  
L. Capone ◽  
P. Ireland ◽  
E. Romero
Keyword(s):  
Flat Plate ◽  
Film Cooling ◽  
High Efficiency ◽  
Nonlinear Effects ◽  
Suction Side ◽  
Complex Problem ◽  
Correct Prediction ◽  
Blowing Ratio ◽  
Key Factor ◽  
Plate Geometry

An optimal design of film cooling is a key factor in the effort of producing high-efficiency gas turbine. Understanding of the fluid dynamics interaction between cooling holes can help engineers to improve overall thermal effectiveness. Correct prediction through modeling is a very complex problem since multiple phenomena are involved such as mixing, turbulence, and heat transfer. The present work performs an investigation of different cooling configurations ranging from single hole up to two rows. The main objective is to evaluate the double-rows interaction and the effect on film cooling. Strong nonlinear effects are underlined by different simulations, while varying blowing ratio (BR) and geometrical configuration of cooling holes. Meanwhile an initial analysis is performed using flat plate geometry, verification and validation is then extended to realistic stage of high pressure (HP) turbine. Multiple cooling holes configurations are embedded on the pressure side (PS) and suction side (SS) of the single stage. The main outcome is the verification of the thermal effectiveness improvement obtained by cooling jets interaction of multiple rows design. The effects of curvature surface and frame of reference rotation are also evaluated, underlying the differences with standard flat plate test cases.

scholarly journals Quantification of Moment–Rotation Relationship of Monolithic Precast Beam–Column Connections

Buildings ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 11
Author(s):  
Baoxi Song ◽  
Weizhi Xu ◽  
Dongsheng Du ◽  
Shuguang Wang
Keyword(s):  
High Efficiency ◽  
Coupling Effect ◽  
Characteristic Point ◽  
Equivalent Model ◽  
Building Structures ◽  
Step Method ◽  
Nonlinear Structural ◽  
The Moment ◽  
Relationship Of

The accurate prediction of nonlinear structural behaviors under different seismic intensities is an important basis for seismic resilience assessments of building structures. The moment–rotation relationship is often used to characterize the seismic performance of connections, and is widely used in high-efficiency nonlinear structural analysis. In this paper, a method of calculating the curve using a four-linear equivalent model is presented, aiming to quantify the characteristic point parameters of the moment–rotation curves of monolithic precast beam–column (MPBC) connections for engineering design purposes. The method considered the contribution of the elastic flexure of beams and columns, the relative slip of beam longitudinal bars in the core zone, and the formation of plastic hinges at beam ends to the total deflection. Due to the presence of local complex configurations in MPBC connections, the fine fiber section method was used for moment–curvature analysis of critical beam sections. The determination of the sectional analysis processes was controlled by the strain of steel bars or concrete or their coupling effect. In addition, a two-step method was proposed to construct the moment–rotation relationship of cruciform beam–column connections for solving the deformation compatibility of beams on both sides of the column caused by asymmetric reinforcement and the strength difference between new and old concrete. To reflect the current manufacturing level of MPBC connections, 58 representative specimens reported in recent years were analyzed and classified as type 1–5. All types of MPBC connections and their 18 cast-in situ counterparts were calculated using the proposed method for both verification and quantification. The verification showed that the proposed method had good applicability to both cast-in situ and precast beam–column connections. The quantification showed that the characteristic point parameters were slightly different between these two connections. Accordingly, modification coefficients were suggested for MPBC connections to facilitate design.

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