bluuebunny/crossref_metadata_2025_split huggingface dataset:
Control-Oriented Modeling for Smart Mesoflap Aeroelastic Recirculation Control (S.M.A.R.T)
Authors: Tharayil Marina , Alleyne Andrew 
Published: November 2021

Abstract
This paper introduces a novel concept termed Smart Mesoflaps for Aeroelastic Recirculation Transpiration (SMART) to render mass and momentum transfer for controlling shock/boundary-layer interactions (SBLI) in supersonic jet inlets. The SMART concept consists of a matrix of small flaps (sub-millimetric in thickness and of smart material composition), which are designed to undergo local aeroelastic deflection to achieve proper mass bleed or injection when subjected to shock loads. Although positive system performance is achieved using this system, the ‘smart’ part of the SMART is utilized to control the flap deflection to optimize the amount of recirculation (and thus the performance). This Thermally-Activated Smart Material (TASM) design uses NiTi shape memory alloy as an actuator for the flaps to control the amount of circulation. The focus of this paper will be the subsystem modeling of a single flap. After a relatively detailed model is developed, a simpler model is used to approximate the system, and it is shown that this approximation is adequate for control purposes. This model is then validated using step responses as well as closed loop experimental data.
Control of Shape Memory Alloy Actuators Using Pulse Width Pulse Frequency (PWPF) Modulation
Authors: Song G. , Ma N. 
Published: November 2021

Abstract
This paper presents the design and experimental results of control of an SMA actuator using PWPF modulation to reduce the energy consumption by the SMA actuator. An SMA wire test stand is used in this research. Based on results of open-loop testing of the SMA wire actuator and parameter analysis of the PWPF modulator, a PWPF modulator is designed to modulate a Proportional plus Derivative (PD) controller. Experiments demonstrate that control of the SMA actuator using PWPF modulation effectively save actuation energy whiling maintaining same control accuracy as compared to continuous PD control.
Impact Damping With Granular Materials
Authors: Saeki Masato 
Published: November 2021

Abstract
The performance of an impact damper with granular materials in horizontally and vertically vibrating systems is investigated both experimentally and analytically. The motion of the damper is solved by the discrete element method, which is often used in investigations of soil mechanics and powder technology. This method makes it possible to consider the effect of granularity on the damping performance. In this method, the dynamics of the entire system is determined by analysis of the motion of the individual particles. The validity of this numerical method is examined by comparison with the experimental results. The difference in the damping effect in horizontally and vertically vibrating systems is considered.
Static Compressive Study of Metallic Cellular Solids: Aluminium Honeycombs and Foams
Authors: Ruan D. , Lu G. , Chen F. L. 
Published: November 2021

Abstract
In this paper the behaviour of both aluminium honeycombs and closed-cell aluminium foams under static loading was investigated. A comparison was conducted between experimental data of foams with various densities and honeycombs with different cell size and cell wall thickness and previous theoretical analysis. In addition, the finite element numerical simulation of honeycomb was carried out. It was found that the numerical simulation results fitted well with the previous theoretical results.
A Meso-Electro-Mechanical Model for PMN-PT-BT Ceramics Behavior
Authors: Fan Jinghong 
Published: November 2021

Abstract
A three-dimensional, meso-electro-mechanical model has been formulated for description of PMN-PT-BT ceramics. Unlike the experimentally fit models and phenomenological models which are based on state variables and/or empirical relationships, this fully coupled, computational mesomechanics model for polycrystalline PMN-PT-BT ceramics is developed based on considerations of constitutive behavior of single crystals. Specifically, domain wall nucleation and evolution rate equations are proposed in this work to describe the nonlinear hysteresis behavior of these ceramics near the phase transition temperature with maximum permittivity.
Development of a PZT Fiber/Piezo-Polymer Composite Actuator With Interdigitated Electrodes
Authors: Kim Cheol , Koo Kun-Hyung 
Published: November 2021

Abstract
Piezoelectric Fiber Composites with Interdigitated Electrodes (PFCIDE) were previously introduced as an alternative to monolithic wafers with conventional electrodes for applications of structural actuation. This paper is an investigation into the performance improvement of piezoelectric fiber composite actuators by changing the matrix material. This paper presents a modified micro-electromechanical model and numerical analyses of piezoelectric fiber/piezopolymer matrix composite actuator with interdigitated electrodes (PFPMIDE).
Various concepts from different backgrounds including three-dimensional linear elastic and dielectric theories have been incorporated into the present linear piezoelectric model. The rule of mixture and the modified method to calculate effective properties of fiber composites were extended to apply to the PFPMIDE model. The new model was validated comparing with available experimental data and other analytical results. To see the structural responses of a composite plate integrated with the PFPMIDE, three-dimensional finite element formulations were derived. Numerical analyses show that the shape of the graphite/epoxy composite plate with the PFPMIDE may be controlled by judicious choice of voltages, piezoelectric fiber angles, and elastic tailoring of the composite plate.
Design of a Robotic Fish Using Shape Memory Alloy (SMA) Wires
Authors: Penney N. , Barr T. A. , Song G. 
Published: November 2021

Abstract
There are several problems with current electro-mechanical or biomechanical robotic fish. All servomotors emit detectable noises when they are operated. This is a major problem when designing a device that needs to remain undetectable, such as a submarine. The cost of hardware and electronics package that is associated with servo devices are generally very high. Another problem is the underwater reliability of sensitive electronics packages in a fresh or saltwater environment, where the possibility of leaking is a real threat. Finally the duplication of natural fish movement with servomotors is a very complex design.
This paper presents a novel design of a robotic fish actuated by shape memory alloy wires. This fish is constructed using an innovative composite skeleton and shape memory alloy wires for the muscle structure. The skeleton of the fish is designed to duplicate a natural fish like movement. Several working models of this type fish have been fabricated in the Smart Materials and Structures Laboratory at The University of Akron. An off-board electronic control package has been designed to actuate the SMA wires and maneuver the fish. The off-board electronic control package mainly consists of a programmable current amplifier and a real-time control system. Experimental results show that fish-like locomotion can be achieved.
By utilizing shape memory alloys instead of servomotors a robotic fish can become as undetectable as a living fish. Smart memory alloys are cheaper and more reliable than servomotors under harsh environmental conditions; the overall cost of the fish may be reduced. Since this fish can reproduce the natural mobility of a living fish without the noise of servomotors, this fish can be utilized in both the commercial fishing industry and the intelligence field.
Actuation Efficiency and Work Flow in Piezoelectrically Driven Systems
Authors: Shi Yong , Hagood Nesbitt W. 
Published: November 2021

Abstract
Previous study indicts that load coupling has significant influence on the work flow and actuation efficiency in the systems. Theoretical coupled analysis has shown that the actuation efficiency is the highest at the stiffness ratio larger than one and this maximum value is much higher than that predicted by the uncoupled analysis. Moreover, for non-linear systems, the actuation efficiency can be twice as high as that of linear systems. The objectives of this research is to verify the theoretical coupled analysis experimentally and explore the possibility for the mechanical work to be done into the environment. The test results exactly proved out the theoretical prediction of linear and non-linear loading systems. The capability of modeling and testing of non-conservative thermodynamic cycles have also been demonstrated which make it possible to take advantage of the mechanical work out of the systems.
Prediction of Water Circulation Characteristics in a 4-Pass Firetube Boiler With the Non-Symmetric Arrangement of Tube Passes 3 and 4
Authors: Park Hyunjae , Bowman Anthony , Stansfield Tod , Huibregtse Brian , Wilkinson Steve , Ayala Willie 
Published: November 2021

Abstract
Water circulation characteristics, for a newly designed 4-pass 300 BHP (Boiler Horse Power) firetube boiler with a non-symmetric arrangement of tube passes 3 and 4, are investigated in this paper by means of measured furnace wall temperatures for different boiler firing conditions. Vapor production rate and intensity, at each of the 28 temperature measurement nodes, is approximated using the nodal temperature in conjunction with a nucleate boiling heat transfer mode on the water side of the furnace. Defining an attraction force that is proportional to the relative difference of the evaporation intensity between two nodes and inversely proportional to the distance between, the two-dimensional components of the attraction force can be calculated. Integrating all attraction force vectors between a node and the surrounding nodes produces a representative attraction force vector at the node. Similar calculation of the attraction force vectors at all of the temperature nodes on the furnace wall will characterize the water circulation near the boiler furnace. Investigations of the analysis results reveal various complicated non-symmetric water circulation patterns for different boiler firing conditions. Consequently, the analysis methods employed in this paper can be used to predict and improve the water circulation in a firetube boiler, particularly with regard to the placement of the boiler feed-water inlet location.
Study on Wrap Profile Modification Using Symmetrical Circular Involute Plus Dual Line-Segment
Authors: Wang Guoliang , Guo Bei , Zhang Wei , Li Liansheng , Shu Pengcheng 
Published: November 2021

Abstract
The scroll machine’s performance is influenced by its wrap profile. The geometry theory of scroll profile at starting part, which is composed of symmetrical circular involute plus dual line-segment, is proposed. The meshing property of the new modified curve is derived. The formula used to caculate the discharge chamber volume when the modified profiles are in mesh are also given. It is emphasized that the modifacation using symmetrical circular arc (for short, SCA) and that using symmetrical circular arc plus dual line-segment (for short, SCAL) are two special cases of that using symmetrical circular involute plus dual line-segment (for short, SCIL).
Evaluation of Conventional Pump Impeller Design Methods by Means of Numerical Calculations
Authors: Karakas A. Askin , Ayder Erkan 
Published: November 2021

Abstract
Conventional methods for the design of radial pump impellers are evaluated by use of computational approaches. Three dimensional continuity and momentum equations for steady incompressible flows are solved by utilizing an artificial compressibility technique. A finite volume method associated with the explicit fourth order modified Runge-Kutta time marching is developed to study the flow in a three dimensional radial impeller, designed by using a streamline curvature method with adaption of emprical formulas.
The developed flow solver provides detailed pressure and velocity distributions inside the radial pump impellers. The comparison of the computationaly calculated and experimentaly measured impeller heads are in agreement especially at the design point of the impeller. Additionally, calculated impeller exit flow conditions, variations of static pressure, total pressure, meridional component of absolute velocity and absolute flow angle from hub to shroud are compared with those measured experimentally.
The Role of CFD in Turbomachinery Design
Authors: Tsuei Hsin-Hua 
Published: November 2021

Abstract
The use of three-dimensional, Navier-Stokes CFD as a practical tool for turbomachinery design is discussed. For a CFD based design procedure to be practical and efficient, the design engineer is required to make a number of important decisions e.g. the minimum level of physics that is required to be simulated which will impact the design outcome, the appropriate level of grid resolution that will be necessary to model this physics. With judicious decisions for these issues, we illustrate that CFD can be integrated effectively into a design iteration process for problems ranging from single blade row design to multiple stage analysis. A wide range of test cases are presented using the pbCFD code which is built upon Dawes’ BTOB3D code. The examples presented here include a range of centrifugal and axial turbomachines. In most cases, solutions are obtained in the order of 10 minutes on a 1GHz Pentium processor with mass convergence error being within 1 percent. Good comparison is shown with data for the final design illustrating the critical role that CFD can play in the design process.
Validation of Design-Based CFD Calculations for a Centrifugal Pump
Authors: Lee Yu-Tai , Tse Michael , Katz Joseph 
Published: November 2021

Abstract
The use of fully unsteady CFD computations for centrifugal turbomachinery during preliminary design calculations is still infeasible due to the extensive computational efforts required. Most design-based CFD analyses for centrifugal machines are conducted on individual components using steady-state calculations. These steady calculations do not represent the interactions of the components with their neighboring blade rows, including the upstream rotating component. In this paper, commonly accepted CFD procedures for steady-state calculations are applied to the components of a centrifugal pump with a shrouded impeller and a vaned diffuser/volute. Evaluation of the validity of these calculations is conducted by comparing the predicted flow field with detailed measurements at the interface between the rotating impeller and the stationary diffuser and volute.
The Performance of R-407C and R-410B in a Residential Window Air-Conditioner With a Liquid-Suction Heat Exchanger
Authors: Kim Man-Hoe , Shin Jeong-Seob , Kim Kwon-Jin 
Published: November 2021

Abstract
This study presents test results of a residential window air-conditioner using R-22 and two potential alternative refrigerants, R-407C and R-410B. A series of performance tests have been carried out for the basic and liquid-suction heat exchange cycles in a psychrometric calorimeter of which the dry and wet bulb temperatures for the indoor and outdoor chambers are 27/19.5°C and 35/24°C, respectively. For R-407C, the same rotary compressor was used as in the R-22 system. The R-410B system was equipped with a newly designed compressor to provide the similar cooling capacity as the baseline system. The liquid-suction heat exchange cycle with the modified counter-cross flow evaporator was considered to improve the system performance. System characteristics such as cooling capacity, energy efficiency ratio, and suction and discharge pressures and heat exchanger temperature profiles are presented, compared to those for the baseline R-22 system. The modified system with a liquid-suction heat exchanger increased cooling capacity and energy efficiency by up to 5%.
Experimental and Theoretical Study of Microturbine-Based BCHP System
Authors: Fairchild P. D. , Labinov S. D. , Zaltash A. , Rizy D. T. 
Published: November 2021

Abstract
On-site and near-site distributed power generation (DG), as part of a Buildings Cooling, Heating and Power (BCHP) system, brings both electricity and waste heat from the DG sources closer to the end user’s electric and thermal loads. Consequently, the waste heat can be used as input power for heat-activated air conditioners, chillers, and desiccant dehumidification systems; to generate steam for space heating; or to provide hot water for laundry, kitchen, cleaning services and/or restrooms. By making use of what is normally waste heat, BCHP systems meet a building’s electrical and thermal loads with a lower input of fossil fuel, yielding resource efficiencies of 40 to 70% or more.
To ensure the success of BCHP systems, interactions of a DG system — such as a microturbine and thermal heat recovery units under steady-state modes of operation with various exhaust backpressures — must be considered. This article studies the performance and emissions of a 30-kW microturbine over a range of design and off-design conditions in steady-state operating mode with various backpressures. In parallel with the experimental part of the project, a BCHP mathematical model was developed describing basic thermodynamic and hydraulic processes in the system, heat and material balances, and the relationship of the balances to the system configuration. The model can determine the efficiency of energy conversion both for an individual microturbine unit and for the entire BCHP system for various system configurations and external loads. Based on actual data from a 30-kW microturbine, linear analysis was used to obtain an analytical relationship between the changes in the thermodynamic and hydraulic parameters of the system. The actual data show that, when the backpressure at the microturbine exhaust outlet is increased to the maximum of 7 in. wc (0.017 atm), the microturbine’s useful power output decreases by from 3.5% at a full power setting of 30 kW to 5.5% at a one-third power setting (10 kW), while the efficiency of the unit decreases from 2.5 to 4.0%, accordingly.
Tests on the microturbine were conducted at the Cooling, Heating, and Power Laboratory set up at the Oak Ridge National Laboratory’s Buildings Technology Center. Data were collected from the microturbine at power demand settings of 30 kW (full load) to 10 kW in 5-kW increments. For each power demand setting, data measurements were taken over an entire range of microturbine exhaust backpressures. The parameters measured were engine speed, ambient air temperature, air temperature at the microturbine inlet, gas temperature at the turbine outlet, exhaust gas temperature, throttle pressure loss, flow rate of natural gas, and composition of combustion products. The mathematical model provided gas temperature before the turbine, compression rate, and air flow rate, which were determined based on the measured data. The results of these early tests and the computer-based simulation model are in very close agreement.
Experimental Study on Characteristics of an Air-Source Heat Pump Under Frosting/Defrosting Conditions
Authors: Peng Xueyuan , Xing Ziwen , Huang Hu , Shu Pengcheng 
Published: November 2021

Abstract
Applications of air-source heat pump are steadily increasing in South China especially in Yangtze River region. Owing to low temperature and high humidity in these areas, frost formation is liable to occur on the outdoor heat exchanger, thus resulting in reduction in performance of the heat pump and even failure of some components such as the compressor and the motor. In order to improve performance and reliability of the air-source heat pump operating in cold and humid climate, rational defrosting control is important, and this should be based on understanding of characteristics of the heat pump operating under frosting/defrosting conditions. In this paper, operating behavior of an air-source heat pump under frosting/defrosting conditions is investigated experimentally. Recorded are dynamic changes in parameters of the heat pump under frosting/defrosting conditions, including suction and discharge pressure of the compressor, temperature of the fin surface, heating capacity, power consumption, electric current of the fan and thickness of the frost layer. Effect of frost formation on performance and reliability of the heat pump is analyzed. It is shown that there is not a great change in operating state as well as performance of the air-source heat pump until the frost layer is accumulated to some extent, and that performance can be improved by taking proper defrosting measurements. Furthermore, rapid changes in suction pressure and discharge pressure under defrosting conditions may result in failure of the compressor and the motor, and therefore, reducing changes in pressure especially of suction is important for improving reliability of the heat pump.
Heat Transfer and Pressure Drop of Evaporating CO2 in Microchannels and System Design Implications of Critical Heat Flux Conditions
Authors: Nekså Petter , Pettersen Jostein , Skaugen Geir 
Published: November 2021

Abstract
Experimental data on heat transfer and pressure drop during near-critical evaporation of carbon dioxide (CO2) in a microchannel aluminium tube are presented. The test tube had 25 circular ports/channels with 0.79 mm inner diameter. The CO2-side heat transfer coefficient was determined by a modified Wilson plot technique. Measured data were compared to correlations available in the literature. For evaporating heat transfer and pressure drop, common correlations did not correspond well to the test data. Under some conditions, the evaporating heat transfer coefficient dropped significantly as the vapour fraction increased. This critical heat flux effect was most pronounced for high heat and mass flux, and high evaporation temperature. Different system designs able to reduce the possible negative effects of critical heat flux are discussed. Negative effects of the phenomenon may be highly reduced if the effect is taken into account when designing the components and the system.