bluuebunny/crossref_metadata_2025_split huggingface dataset:
Between Worlds: Exploring the Links Between the Tangible and Intangible Costs of Prototypes
Authors: Nelson Jacob , Menold Jessica 
Published: October 2020

Abstract
Prototyping is an important part of the design process, but researchers currently have a limited understanding of how the resources invested in a prototype or designer teams’ intent for a prototype influence decision-making and perceptions of a prototype’s value. Prior work has shown that significant investment of time or money in design tasks can lead to design fixation, but little work has explored how these factors might impact design teams’ perceived value of prototypes with respect to the design process. Likewise, it is unclear how resource allocation and prototype intention effects the evolution of design team knowledge and subsequent design actions. To explore these relationships, an in situ study of prototyping tendencies was performed across two mechanical engineering design courses. Results suggest that effective design teams leveraged prototypes to uncover new design knowledge and limit uncertainty early in the design process. Importantly, this study did not find any significant relationships between the cost of a prototype in terms of money and time, and the perceived value of that prototype. Nor were any significant relationships found between costs and final design outcomes. Findings suggest that the true cost and value of a prototype with respect to design outcomes are challenging to explicitly quantify.
Verification of Manual Digitization Methods During Experimental Simulation of Knee Motion
Authors: Hargett Zachary , Gutierrez Manuel , Harman Melinda 
Published: October 2020

Abstract
Cadaveric testing is a common approach for verifying mathematical algorithms in computational modeling. In models of total knee replacement (TKR) motion, model inputs commonly include rigid body motions defined using the Grood–Suntay spatial linkage between tibial and femoral components. This approach requires definition of coordinate systems for each rigid TKR component based on fiducial points, manual digitization of a point cloud within the experimental setup, and registration of the orientation relative to bone marker arrays. This study compared variability between two different manual point digitization methods (hand-held stylus and pivot tool each registered in an optical tracking system). This was accomplished by verifying the mathematical algorithm used to calculate the coordinate system from digitized points and quantifying the variability of the digitization methods in a simulated cadaver limb experimental setup. For the hand-held stylus method, the standard deviation was 0.50 mm for the origin and 1.31, 0.51, and 0.62 deg for the x–y–z axes, respectively. Required digitization of each rigid marker array created additional errors of 0.54 mm for the origin and 1.70, 1.66, and 0.98 deg for the x–y–z axes, respectively. For the pivot tool method, the standard deviation was 0.35 mm for the origin and 0.37, 1.27, and 1.24 deg for the x–y–z axes, respectively. In this experimental setup, the pivot tool was the better option for minimizing error while providing repeatable manual digitization of fiducial points and point clouds.
Reliability Assessment Based on Multisource Information Fusion Method for High Pressure Natural Gas Compressors
Authors: Zhou Dengji , Wei Tingting , Huang Dawen , Liang Maozong , Zhang Huisheng , Weng Shilie , Jiang Ping 
Published: October 2020

Abstract
Compressor units used for long-distance transportation natural gas pipeline pressurization have high-pressure and high-risk characteristics. Hence, the scientific reliability assessment is important for high-pressure compressor units, to evaluate the reliability standard, find the performance deficiency, and provide references for operation and maintenance. The classical reliability assessment method is not suitable for the complex and high-reliability equipment, like high-pressure compressor units and pipelines. The reliability assessment of the high-reliability equipment is faced with the challenge of the multisource information. A reliability assessment method based on the multisource information fusion is proposed in this work. The fusion resources consist of design information, component test information, and trial operation information. The reliability of high-pressure compressor units can be assessed by fusing the characteristic parameters, from component-based assessment, function-based assessment, quality evaluation, and life model, by D–S evidence theory. A case study is conducted to verify the proposed reliability assessment method in a 20 MW-class high-pressure compressor. There are four information resources in the case, i.e., component test data, design information, operation data, and simulation data. The compressor reliability is assessed as 99.32%, validated by the statistical assessment result based on long-term shutdown reports. This application points out the existing weakness in the high-pressure compressor units and indicates the directions for improving the design, analysis, operation, and failure prevention technologies. It reveals that the reliability assessment based on multisource information can provide a guarantee for the operation and maintenance of high-pressure compressor units. Meanwhile, the proposed method has good expansibility, which may be used in more fields.
Pressurized Water Reactor Mixed Oxide/UO2 Transient Benchmark Calculations Using Monte Carlo Serpent 2 Code and Open Nodal Core Simulator ADPRES
Authors: Imron Muhammad , Hartanto Donny 
Published: October 2020

Abstract
This paper presents static and transient solutions for the pressurized water reactor (PWR) MOX/UO2 transient benchmark by Serpent 2 Monte Carlo (MC) code and open nodal core simulator called Abu Dhabi Polytechnic Reactor Simulator (ADPRES). The presence of mixed oxide (MOX) fuels and burn-up variation in the benchmark pose challenges for reactor simulators due to severe flux gradient across fuel assemblies. In this work, the two-step method was used, in which the assembly level two-group constants were generated from single assembly calculations with zero net current boundary conditions using Serpent 2 Monte Carlo code, and later the core calculation was performed using ADPRES open nodal core simulator. Two types of diffusion coefficients were generated: the conventional B1 leakage corrected and the cumulative migration method (CMM). Finally, the solutions of Serpent 2/ADPRES, including multiplication factor, power distribution, control rod (CR) worth, and critical boron concentration (CBC) using both diffusion coefficients, were compared against solutions from heterogeneous Serpent 2 calculations where the fuel and cladding are explicitly modeled. The reactor power during transients was also compared qualitatively against other nodal core simulators. The results showed that Serpent 2/ADPRES were able to predict the heterogeneous Monte Carlo solutions very well with reasonable differences. The transient solutions were also quite accurate compared to other nodal core simulators. For the diffusion coefficients comparison, it was found that the CMM diffusion coefficient provides more accurate solutions for the benchmark compared to the B1 leakage corrected diffusion coefficients.
Thermodynamic Analysis of a Highly Pressurized CO2 Cycle for Renewable Energy Applications
Authors: Kemmerer Geoffrey R. , Gross Thomas , Anderson Kevin R. 
Published: October 2020

Abstract
Refrigerated gases have been used to store energy with limited success. This paper presents the results of an exploratory study of how the behavior of fluids compressed to high pressures can be used to increase the efficiency of refrigeration cycles and one possible application for renewable energy. This research presents the results of thermodynamic modeling and analysis of a novel Carbon Dioxide (CO2) cycle to be used for alternative energy production. The thermodynamic computational simulations are carried out in MATLAB and use the NIST REFPROP database for modeling the high pressure (on the order of 1000 MPa) CO2 state points. Preliminary results show that the maximum energy that can be recovered using the proposed high pressure cycle in on the order of 11,043 J, for each mole of CO2 flowing in the cycle. Thus the Coefficient of Performance is COP = 2.22, and the efficiency of the cycle is estimated as η = 35%. Future work will focus on the development of equipment such as the cryogenic turbo-expander that can operate at the ultra-high pressures studied.
Four-Phase Flow of Oil, Gas, Water, and Sand Mixtures in Subsea Pipelines
Authors: Odan Mohamed , Ben Rajeb Faraj , Rahman Mohammad Azizur , Aborig Amer , Imtiaz Syed , Zhang Yan , Awad Mohamed M. 
Published: October 2020

Abstract
This paper investigates issues around four-phase (Oil/CO2/water/sand) flows occurring within subsea pipelines. Multi-phase flows are the norm, as production fluid from reservoirs typically include sand with water. However, these multi-phase flow mixtures, whether three- or four-phase, are at risk of forming slug flows. The inclusion of sand in this mixture is concerning, as it not only leads to increased levels of pipeline erosion but it also has the potential, to accumulate sand at the bottom of the pipe, blocking the pipe or at the very least hindering the flow. This latter impact can prove problematic, as a minimum fluid velocity must be maintained to ensure the safe and regulated flow of particles along a pipeline. The presence of low amounts of sand particles in oil/gas/water flow mixtures can serve to reduce the pressure exerted on bends. The sand volume fraction must in this case, be relatively low such that the particles’ resistance causes only a moderate loss in pressure. Therefore, the study aims to gauge the impact of oil/gas/water/sand mixtures on various pipeline structures as well as to further investigate the phenomenon of flow-induced vibration to determine the optimal flow variables which can be applied predicting the structural responses of subsea pipelines.
The Influence of Connecting Pipe on Surge Water Level and Water Hammer Pressure in Surge Tank
Authors: Li Gaohui , Zhang Lin , Zhou Tianchi 
Published: October 2020

Abstract
In the calculation of the traditional large fluctuation transition process, the influence of the connecting pipe at the bottom of the surge tank is often considered as the impedance hole. When the connecting pipe is long, the elasticity of the connecting pipe is neglected, which is liable to cause a large error. The surge joint have been mathematically modelized in two ways: with and without its connection to the pipe. Then these models have been used with the Gardel’s formula to treat the impulse coefficient of the surge tank. This study have been combined with concrete examples in order to figure out the influence of the connecting pipe’s diameter and length on the surge tank pressure, inlet pressure and unit speed of the surge tank. If the length of the linking pipe is too long, it would be necessary to consider its role. If the area of the linking pipe is too small, the surge tank will not be able to operate properly, causing water hammer waves.
Effect of Active and Passive Curvature on the Hydrodynamic Performance of Flapping Fins
Authors: Fernández-Gutiérrez David , van Rees Wim M. 
Published: October 2020

Abstract
Ray-finned fish swim by flapping their fins, which are composed of bony rays connected by an inextensible membrane. Throughout the flapping cycle, the fins typically undergo both ‘passive’ deformation due to hydrodynamic loading, and ‘active’ deformation arising from internal musculature deforming the fin against the flow. To systematically analyze the impact of fin shape on hydrodynamic performance, a parametric definition of the fin geometry and its modes of deformation is required, consistent with the fin’s material and mechanical properties. In this paper we present a model and algorithm to determine the fin shape corresponding to an arbitrary out-of-plane curvature distribution for each ray. The shape is computed by iteratively enforcing constraints corresponding to membrane inextensibility, and negligible torsional stiffness of the rays. Based on this model, we present a low-order parametrization of fin shapes that capture the predominant deformation modes due to combined hydrodynamic loading and intrinsic actuation, as compared to experimental observations. To demonstrate the model’s ability to provide insight into the effect of curvature on hydrodynamic fin performance, we integrate our algorithm into a 3D Navier-Stokes solver Using this framework, we present initial results on the cycle-averaged thrust coefficient of a passively and actively deforming generalized trapezoidal caudal fin model at Reynolds number 1500 and Strouhal number 0.3. The results demonstrate that our model, algorithm, and integration with the flow solver form a useful framework to understand the effect of 3D curvature on hydrodynamic performance of flapping fins.
Flow Measurement With a Helical Strake Type Thermowell in Flow Measurement Standard Systems
Authors: Kim Kisung , Lee Sibok , Chun Sejong 
Published: October 2020

Abstract
Helical strake type thermowells are replacing standard thermowells according to ASME PTC 19.3 TW-2016 in various industrial sectors. It is because the helical strakes can suppress the flow-induced vibration by Kármán vortex street over a thermowell. However, the ASME PTC 19.3 TW-2016 does not regulate the helical strakes because their design rules are too complicated to be specified.
This study attempts to characterize the effect of helical strakes on the thermowell vibrations by measuring pressure and strain signals at the same time. The pressure signal is expected to give information on the Kármán vortex street while the strain signal gives the flow-induced vibration on the thermowells. Relative vibration energy or relative vibration amplitude is defined to calculate the efficiency of suppressing the Kármán vortex street around the thermowells.
CFD Evaluation of Blood Flow in an Improved Blalock-Taussig Shunt Using Patient Specific Geometries
Authors: Lin Zhenghao , Agarwal Ramesh K. , Govindarajan Vijay , Schultz Noah , Hoganson David , Hammer Peter 
Published: October 2020

Abstract
Blalock-Taussig (BT) Shunt is a palliative surgical procedure used during a Norwood surgery on a newborn baby suffering from cyanotic heart defects. The BT Shunt can increase blood flow in patients’ pulmonary artery which can ease the “Blue Baby Syndrome.” Currently used BT Shunts do not produce a balanced flow distribution to the pulmonary arteries (PAs) which can cause high wall shear stress (WSS) and blood flow separation resulting in blood clots. A modified BT Shunt was designed to partially solve this problem. In our previous work [1], the modified BT Shunt was shown by numerical simulations to have the ability to better control the flow distribution between Innominate Artery (IA) and PA with lower and gradually varying WSS and with improved flow balance to the pulmonary artery at the T-junction of the shunt.
The goal of this paper is to computationally evaluate the flow in the modified BT shunt model between innominate and pulmonary artery using a patient specific aorta model. The simulations are performed using the commercial CFD software ANSYS Fluent. The improved modified BT shunt is connected between IA and PA. A change in the length of the shunt can be made to fit it under different conditions of actual patients. In numerical simulations, a full geometry of patient’s aorta is considered. Results for different lengths of the shunt are compared to determine the length that generates the lowest WSS and improved flow distribution to the PAs. It was found that the length of nearly 26mm creates lower WSS and flow rate difference between the two sides of PA at the T-junction attachment of the shunt. A sophisticated computational model was created using SolidWorks and Blender software to create the realistic geometry which included the IA, PA and modified BT shunt. The numerical simulations provide details of the flow field including velocity and pressure field, WSS, and blood damage. Several parameters in shunt design weigh heavily in reducing the thrombosis. This study demonstrates how CFD can be effectively utilized in the design of a medical device such as BT shunt to improve the clinical outcomes in patients.
Bubbling Flow in a Multi-Jet Fluidized Bed
Authors: Wang Liwu , Zhang Sijun 
Published: October 2020

Abstract
This work concerns with numerical simulation of dense gas-particle two-phase flow in a fluidized bed in the framework of two-fluid model, where attention is given to the bubble formation in a single-jet and multi-jet fluidized beds. The kinetic theory is implemented in the model to avoid empirically determined model parameters. The validity of the approach is confirmed through the comparison between the computed results and the measurements in the literature. The results show that increasing the number of jets results in different behavior in bubble formation and the flow pattern in a multi-jet bed is much more complex than that in a single-jet bed.
Analysis of Blood Flow Patterns to Estimate Atherosclerosis Formation in the Left Carotid Artery by CFD Simulation
Authors: Momin Marzia , Ara Nusrat , Arafat M. Tarik 
Published: October 2020

Abstract
The purpose of this computational fluid dynamics (CFD) study is to simulate left carotid artery models to evaluate the influence of hematocrit (Hct) level and angle of bifurcation on the formation of atherosclerosis. Bifurcation angle can vary from person to person based on sex, age or diseased condition which has an impact on hemo-dynamic parameters. From the anatomical study, it is seen that the carotid artery bifurcation is the preferential region for atherosclerosis formation. The combination of bifurcation, curvature and diameter change in this bifurcation region causes the blood flow to be complex with recirculation regions and secondary flows which influence hemodynamic changes and the formation of atherosclerosis. Along with the bifurcation angle, the Hct level also influences on changing hemodynamic parameters. As the viscosity of blood is mainly controlled by the Hct level, the hemodynamic parameters of blood are changed on the basis of change in percentage of the Hct level. Therefore, the Hct percentage can act as a risk factor for atherosclerosis formation. We have assessed the probability of vulnerable atherosclerosis formation based on the change of both bifurcation angle and hematocrit level. In this study, three different carotid artery geometries with 40 degree, 48.5 degree, and 63.6 degree angles were simulated at a varying percentage of the Hct level. We discerned these models by using CFD simulation to calculate wall shear stress (WSS), time-averaged wall shear stress (TAWSS) and velocity. The effects of angulation and Hct percentage on the velocity of blood were studied on the plane of the bifurcation region. The carotid artery with 63.6 degree angulation faces more recirculation areas and peak recirculation areas are observed at 25% Hct level. This justifies the reason behind atherosclerosis formation in the artery. We observed low WSS at wider angled models and a high WSS at narrow angled models. WSS value is also affected by the percentage of Hct. In this study, we noticed a lower value of WSS at a lower percentage of Hct which is responsible for atherosclerosis formation. The WSS value of 0.4 Pa was considered as the critical point for the atherosclerosis formation. We also calculated time-averaged wall shear stress (TAWSS) which is similar to the WSS contour plot. Overall, after analyzing the results of velocity, WSS and TAWSS, we concluded that low Hct (around 25% or lower) along with higher bifurcation angle (around 63.6 degree or higher) are more accountable for atherosclerosis formation.
Computational Study of Pump Turbine: Partial Load Operations
Authors: Altimemy Muhannad , Caspar Justin , Oztekin Alparslan 
Published: October 2020

Abstract
The performance of a pump-turbine under partial flow rates, 85%, 75%, and 65%, is studied using the LES model. The power signal, velocity, vorticity, and pressure field is presented over the blades and throughout the draft tube. Pressure fluctuations are probed at various locations over the wall of the draft tube. Examining the flow field in the blade region can provide further insights into the system performance. Flow-induced pressure fluctuations can disrupt system stability.
For this turbine, a strong swirling region is observed around the draft tube walls, causing pressure fluctuations. The size and intensity of this region decrease with the flow rate. A vortex rope is present in all cases. At the design point, the strength is constant throughout the draft tube. However, at partial load, the rope is weakened along the draft tube. Between the region dominated by the vortex rope and the wall, there is a swirling shear layer, which moves closer to the wall as the flow rate decreases.
Both the magnitude of pressure fluctuations at the wall and the pressure difference over the blade decrease with the flow rate. The decreased pressure differences over the blade represent less power produced, and the decline in fluctuation magnitude at the wall represents more system stability. For this turbine, there appears to be a trade-off between power and strength of pressure fluctuations.
Feasibility Study for Flow-Induced Vibration in Stud Pipe Using Computational Fluid Dynamics
Authors: Nguyen Khac-Ha , Kim Won-Tae , Hong Seung-Pyo , Lee Haein , Lee Ahram 
Published: October 2020

Abstract
Piping systems in a nuclear plant can be damaged by high-cycle fatigue due to acoustic-induced vibration. Moreover, if the frequency of the vibration in the piping system is overlapped with a natural frequency of the piping, the magnitude of the amplitude will be increased resulting in many problems. For example, the damage is considered as flow-induced acoustic resonance at the branch pipes of the safety relief valve in the main steam lines. This study has investigated the Computational Fluid Dynamics (CFD) analysis methodology to predict and quantify the vortex shedding frequencies and the pressure pulsation magnitude in the dead-end piping system. In order to estimate the vortex shedding vibration, a high level turbulent model should be applied. Such a turbulent model, however, requires a substantial amount of computing time. Therefore, the purpose of the study is to investigate the effects of the main pipe length and the sublayer inflation rate on the vortex shedding frequency and pressure pulsation magnitude. The results for the effects will be able to reduce the size of the fluid domain so that the computing time can be significantly decreased in using the high resolution turbulent models.