bluuebunny/crossref_metadata_2025_split huggingface dataset:
Traveling of Oscillating Vortices and Its Thermal Effects in a Bending Channel
Authors: Zhong Geyu , Zhang Chuanyu , Guo Xiaofeng , Yang Peng , Liu Yingwen 
Published: November 2022

Abstract
Driven by the periodical reverse of flow orientation, vortices in oscillatory flow induce a local high-speed and low-pressure flow region near the wall, which brings complex physical phenomena to viscous dissipation and heat transfer. This research focuses on the above-mentioned features by relating Spatio-temporal relationships between fluid dynamics and energy transmission. A two-dimensional oscillation model working in a thermoacoustic resonator is developed, considering heating and cooling processes in bending channels. We address oscillatory vortices' formation and transmission process in the bending channel. The acoustic streaming velocity field is obtained by postprocessing and proved to be the primary mechanism to induce spatial vortices in the vicinity of the entrance. The transferring vortices caused by the bending channel are like mini-pumps occupying fluid regions, which contribute to the local enhanced heat transfer performance and are influenced by the wall boundary conditions. The result also shows that skin friction in bending channels occupies about 10%–30% of total resistance, and the driving ratio is more sensitive to viscous dissipation than the wavy height of the bending channel. This study provides an approach to understanding the underlying mechanisms of heat transfer enhancement from hydrodynamics and inspiration to design compact heat exchangers employed in the oscillating flow.
Determination of the Optimum Operating Conditions and Geometrical Dimensions of the Plate Fin Heat Sinks Using Teaching-Learning-Based-Optimization Algorithm
Authors: Kuru Muhammet Nasıf 
Published: November 2022

Abstract
Electronic devices must be effectively cooled for long-term reliability and safe operation. It is essential to determine operating conditions and optimum dimensions of cooling devices in terms of device weight, space, cost, and sound limits. Plate fin heat sinks (PFHSs) are frequently used for cooling electronic devices. Optimum thermal designs of PFHSs are explored in this study using a teaching-learning-based-optimization (TLBO) algorithm where entropy generation (S˙gen) minimization, profit factor (J) maximization, base plate temperature excess (θb) minimization, total mass (mass) minimization, and total volume (volume) minimization are the objective functions of the constrained single-objective optimization problems. For further investigations of the entropy generation minimization method, three different optimization problems are also studied: minimization of thermal resistance (Rth), minimization of pressure drop (ΔP), and minimization of pumping power (W˙pump). Each optimization problem is subjected to a constraint, namely, temperature excess of base plate temperature (θb) should be lower than 10 K. Four optimization variables are considered which are the number of plate fins (N), freestream velocity (Vf), the thickness of the fin (tfin), and height of the fin (Hfin). Optimum configurations belonging to the different optimization problems are compared, and the effect of each optimization variable on the objective functions is discussed in detail. It is found that one can obtain optimum operating conditions and geometrical dimensions of the PFHSs according to the design objective, i.e., minimum mass requirement, space limitation, minimum base plate requirement, etc. As a result, the optimum designs of the studied cases are different which are superior to each other in terms of design targets.
Low Frequency Waterborne Sound Insulation Based on Sandwich Panels With Quasi-Zero-Stiffness Truss Core
Authors: Wang Dongwei , Zhang Quan , Hu Gengkai 
Published: November 2022

Abstract
Due to the negative correlation between pressure resistance and waterborne sound insulation, low-impedance soundproof materials can hardly work in deep water. Here, we propose a new mechanism to circumvent this problem by employing a sandwich panel with designed dynamics quasi-zero-stiffness (QZS) truss cores. The latticed cores are made of programable curved beams, whose shape is carefully designed to meet the demand of both high-pressure resistance and dynamics QZS. An analytical model is developed to evaluate sound transmission of such panel. It is shown that the low-frequency sound insulation performance of the customized panel increases with the hydrostatic pressure and reaches its maximum when the QZS state is triggered. The effective pressure range of the proposed sandwich panel can be further programed by stacking QZS beam lattices of different static load plateaus. The proposed design strategy stems solely from the structural geometry of the curved beams and is therefore materials-insensitive. The linear/inverse relationships between static loading feature and characteristic mechanical properties/geometrical parameters, and the stacking arrangement of lattice bring out the programability of the panel’s bearing capacity. The design strategy, together with the established database, provides a feasible approach for underwater sound insulation of equipment subjected to elevated pressures.
Minimizing Boundary Friction in Diesel Engines Piston Assembly: Testing the Rotating Liner Engine Prototype Under Load
Authors: Dardalis Dimitrios , Basu Amiyo K. , Hall Matt J. , Matthews Ronald D. 
Published: November 2022

Abstract
The Rotating Liner Engine (RLE) is a design concept where the cylinder liner of a heavy-duty Diesel engine rotates at about 2–4 m/s surface speed to eliminate the piston ring and skirt boundary friction near the top and bottom dead center. Based on prior testing results from our single cylinder RLE prototype (a converted four-cylinder Cummins ISB 3.9 Diesel) compared to a similar baseline, under idle conditions, the friction reduction is approximately 50 kPa (0.5 bar) in FMEP (friction mean effective pressure), which translates to about 40% for a complete engine. In this new set of experiments, we compare the RLE performance under load of up to about 7 bar IMEP (indicated mean effective pressure). It has been proven that the elimination of metallic contact between the compression rings and cylinder wall persists for up to 75 bar peak cylinder pressure and 1.5–2.3 m/s liner surface speed (283–426 rpm) for the 850–1280 rpm crankshaft speed. Additionally, the RLE FMEP is substantially reduced under load, which is a trend opposite to standard engines. Presumably, at idle the RLE cylinder and piston are cooler than the standard engine because the substantial heat dissipation by the metallic contact of the rings and skirts with the liner does not take place. Under load, however, the increased heat transfer from the combustion raises a piston and rotating cylinder temperatures, which reduces local lubricant viscosity and reduces mid-stroke viscous losses as well as rotating liner parasitic losses. Furthermore, based on higher speed baseline engine data, it appears that there is also a reduction in the hydrodynamic piston terms. The reason is attributed to the increased lubricant film thickness at mid-stroke, due to the combined effects of the liner rotation and the traditional wedge effects of the piston skirt and rings. This effect seems to more than compensate for the increase of the hydrodynamic parasitic friction of the liner rotation with engine speed (we currently have a constant 3:1 ratio of the crankshaft to liner speed). The combined fuel efficiency benefit is shown to exceed 10% for medium loads and speeds.
Modeling the Liquid Properties of E10 Gasoline for Application in Hydraulic and Combustion System Simulations at High Injection Pressures – Validation With Experimental Measurements
Authors: Tzanetakis Tom , Park Ji-Woong , Voice Alexander K. 
Published: November 2022

Abstract
Gasoline compression ignition (GCI) is an internal combustion engine technology that can improve the soot-NOx tradeoff and CO2 emissions of conventional diesel powertrains. GCI also offers a pathway to alleviate the operational and durability demands being placed on current lean aftertreatment systems for meeting upcoming criteria pollutant regulations. High-pressure fuel injection equipment is a key enabling subsystem for GCI and optimization along with the combustion, air and aftertreatment systems requires the use of simulation-based design tools like 1D hydraulic models or 3D-CFD. However, these tools require fuel property specifications to accurately capture the flow, spray, and combustion processes at conditions relevant to GCI. This work presents a surrogate formulation methodology that matches the entire measured chemical species listing of any gasoline as closely as possible and generates the required fuel properties over a specified range. It can be used when direct determination is not feasible or when properties are unknown at every condition of interest. Measurements of liquid density, viscosity, heat capacity and thermal conductivity were conducted on E10 certification gasoline from −20 to 150°C and 0–2500 bar (g) to validate the calculation methodology. Density did not exceed 1.6% difference with measured data, while heat capacity remained within 27%. Viscosity and thermal conductivity had maximum errors of 173% and 46%, respectively. This was due to the lack of appropriate pressure dependencies for these properties in the calculation methodology. The maximum error in modeled viscosity was reduced to 53% after employing a simple viscosity-pressure correlation for generic hydrocarbons.
Sooting Behavior of Commercial and Bio-Derived Butyl-Acetate/N-Heptane Blends in High-Pressure Spray Combustion Experiments
Authors: Stevenson Anna L. , Parker Allen J. , Reggeti Shawn A. , Agrawal Ajay K. , Bittle Joshua A. 
Published: November 2022

Abstract
The desire to use diesel blended with biofuels has accelerated in an effort to reduce reliance on non-renewable resources as well as reduce emissions from the heavy-duty portion of the transportation sector. Of particular interest are oxygenated compounds, notably esters, which have the potential to reduce the sooting tendency of diesel fuel. Butyl-acetate (BA) is one such ester with favorable properties as a fuel additive though perhaps not an obvious choice for a mixing controlled compression ignition engine due to its low cetane number. Despite this, if demonstrated to be able to reduced soot emissions when blended with diesel this blend candidate may be worth more study as a new bio-derived, low-energy, microbial fermentation process for production of BA shows promise for cost effective, high volume production. In this study, a constant-pressure flow chamber is utilized to observe fuel injection, mixing, ignition and combustion characteristics of commercial- and bio-BA blended with diesel surrogate n-heptane as a first study of its kind in a diesel-like fuel spray. Rainbow schlieren deflectometry, OH* chemiluminescence, and two-color pyrometry are utilized to quantify global parameters including ignition delay time, liquid length, vapor penetration, lift-off length, and soot mass. The results presented show that blending BA into n-heptane is effective at reducing soot emissions; moreover, the commercial-BA blend and the bio-BA blend are equally effective at reducing soot emissions. Future work will explore more test conditions, different blend ratios, and engine operation.
Simulation of Spray, Wall-Film, and Charge Preparation for Light-Duty, Cold-Start Applications
Authors: Edwards K. Dean 
Published: November 2022

Abstract
For modern, light-duty engine applications, the development of improved operating strategies to expedite catalyst heating during cold-start operation is essential for further reduction of emissions and meeting of future regulations. The development of such strategies would benefit from numerical modeling tools capable of accurate prediction of charge preparation, combustion, and emissions formation at cold-start conditions. Traditional development of simulation tools has primarily focused on standard engine operating conditions, and, as a result, these tools have difficulty accurately capturing extreme behavior during cold-start operation such as extensive wall wetting due to fuel-spray impingement on cold cylinder surfaces, late combustion phasing to increase exhaust enthalpy, and continued oxidation of reactants in the exhaust system. A major objective of the multi-national-laboratory Partnership to Advance Combustion Engines (PACE) consortium is the development and evaluation of new modeling approaches for cold-start operation. In this paper, we present recent progress in simulating charge preparation in a light-duty, multi-cylinder, gasoline engine during cold-start relevant conditions as defined by the U.S. DRIVE Advanced Combustion and Emission Control (ACEC) Tech Team cold-start protocols for catalyst heating. We focus study on fuel spray and spray-wall interactions resulting in extensive film formation due to cold cylinder walls. Simulation results are evaluated at steady-state, cold-start relevant operating conditions. Predictions for film formation and composition with conventional (baseline) models are compared to results with new simulation tools and approaches developed under PACE including the Corrective Distortion Spray Model developed by Sandia National Laboratories, which accounts for non-spherical droplet shapes, and a new spray-wall interaction model developed by Argonne National Laboratory, which accounts for multi-droplet, non-uniform impingement. The current study expands on past studies validating these new submodels with spray-chamber experimental measurements to examine the impact they have on full engine CFD simulations.
Predicting the Cetane Number, Sooting Tendency, and Energy Density of Terpene Fuel Additives
Authors: Kessler Travis , SubLaban Amina , Mack J. Hunter 
Published: November 2022

Abstract
Discovering renewable fuels and fuel additives is paramount in reducing carbon emissions from internal combustion engines. Terpenes, a group of compounds that can be synthesized from plant matter and microorganisms, have gained significant interest in recent years as promising candidates for fuels/additives. Terpenes are a diverse class of compounds that contain rings and methyl branches, resulting in high energy densities and optimal cold weather behavior. Their variation in bond order, carbon chains, and functional groups lead to varying degrees of soot formation and performance in existing engines. The present work leverages predictive models, namely artificial neural networks, to predict the cetane number (CN), sooting tendency (quantified with yield sooting index, YSI), and energy density (quantified with lower heating value, LHV) of terpenes and hydrogenated terpenes whose sooting propensities were previously determined through experimental means. Predicted sooting propensities of these terpenes are compared with experimental values, and predicted cetane numbers and energy densities are used to comment on the compounds’ ability to act as fuels/additives. Expected prediction errors for CN, YSI, and LHV, defined by blind test set median absolute error, are within 5.56 cetane units, 3.63 yield sooting index units, and 0.77 MJ/kg respectively. Additionally, the present work investigates a variety of correlation/dependence metrics for property-property relationships, furthering our understanding of how combustion-relevant properties are related.
Dynamic Modeling of the Supercritical Carbon Dioxide Simple Recuperated Brayton Cycle
Authors: Song Ping , Zhao Zhenxing , Dai Chunhui , Chen Lie , Yang Xiaohu , Wang Wei , Li Shaodan , Ma Can , Lao Xingsheng 
Published: November 2022

Abstract
With the development of the GEN-IV nuclear reactors in the 21st Century, as a substitute for the steam cycle, the supercritical carbon dioxide (SCO2) Brayton cycle has been widely used in a variety of power generation scenarios and has attracted widely attention from the scholars. However, the previous research mainly focused on the basic thermodynamics research, parameter optimizations and system design. Considering the load variability and control flexibility of the power generation system, the dynamic performance research of the SCO2 cycle is necessary. In the numerous layouts of SCO2 Brayton cycle, the SCO2 simple recuperated cycle stands out for its simple structure and high efficiency, which is also the main focus in this paper. In this paper, a dynamic model of SCO2 simple recuperated brayton cycle is developed with the Simulink software. The overall system includes a turbine (T), compressor (CM), regenerator (Re), intermediate heat exchanger (IHE), pre-cooler (PC), surge tank (ST), and heater. The models could be able to realize independent physical functions and be mathematically independent. The SCO2 recuperated cycle is then built with the developed models. Based on the simple recuperated system, the comparative calculation with the design value is carried out to verify the models and the results are very positive. Since the components are tightly coupled in the closed-loop cycle, the error of the main parameters for each component is relatively large. In the steady calculation, the maximum error of the component parameter is 7.72%, and the error of the cycle efficiency is about 1.45%. The results are very promising that the developed model has the ability to evaluate the thermal-hydraulic characteristics of the SCO2 Brayton circulation system.
Evaluation on Weldability of Nickel-Base Alloy Weld Materials With High Chromium Content
Authors: Katayama Yoshinori , Hayashi Takahiro , Tanaka Daiki , Takahashi Hidenori 
Published: November 2022

Abstract
Nickel (Ni)-base alloy 82 weld material is widely used for the primary reactor components of boiling water reactor (BWR). Although alloy 82 has shown excellent service performance for BWR application in terms of material reliability, several experiences have recently been reported regarding stress corrosion cracking (SCC) in welds associated with alloy 82. The present study aimed at enhancing SCC resistance of the weld material by developing and evaluating alloy 82 with increased chromium (Cr) content of 30%, 33% and 36%. Weld joint specimens were prepared by tungsten inert gas (TIG) welding with the prototyped wires of alloy 82 with increased Cr content. The mechanical properties and weldability were investigated using the weld joint specimens. For comparison, the conventional alloy 82 and alloy 52 were also tested. The mechanical properties of alloy 82 with increased Cr content were equal to or better than those of the conventional alloy 82. Varestraint test and bending test were carried out to determine the weldability. In the Varestraint test, the susceptibility to solidification cracking and ductility-dip cracking were evaluated. The temperature ranges of the ductility-dip cracking of the alloy 82 with increased Cr content was about the same as that of the conventional alloy 82. As a result of these tests, it was confirmed that the alloy 82 with increased Cr content has the same weldability as that of the conventional alloy 82 and was applicable for BWR components.
The Optimal Theta of Optimally Diffusive Coarse Mesh Finite Difference Method to Accelerate DGFEM Based SN
Authors: Kong Boran , Zhang Han , Zhu Kaijie , Hao Chen , Guo Jiong , Li Fu 
Published: November 2022

Abstract
Optimally diffusive coarse mesh finite difference (odCMFD) method is a recently developed acceleration method for neutron transport equation. Compared with the traditional CMFD, it adds an optimal theta on the diffusion coefficient. This new acceleration method achieves a higher convergence rate than the traditional CMFD and promises the convergence even in large optical thickness region. However, the optimal theta of odCMFD is determined by the Fourier analysis results of the 1D traditional SN. When applying the odCMFD to accelerate DGFEM based SN, this optimal theta is not always suitable. Therefore, it is necessary to find a new optimal theta for this new scheme. In this paper, a Fourier analysis of DGFEM based SN using odCMFD acceleration for k-eigenvalue neutron transport problem is conducted. Fourier analysis results show that when the number of inner iterations is higher than 10, the increment of the inner iterations has little impact on the spectral radius. Meanwhile, the order of the DGFEM based SN and the order of SN quadrature set have little impact on the spectral radius. The scattering ratio has great impact on the spectral radius, the decrement of scattering ratio increases the spectral radius. Set the number of inner iterations as 10, for different scattering ratio, an optimal theta of odCMFD and a polynomial fitting curve are obtained by Fourier analysis. Finally, numerical estimations of spectral radius are obtained by real 1D DGFEM based SN calculation with odCMFD acceleration. The experiment values fit well with the Fourier analysis theoretical results.
Research on Crack Resistance of Nuclear Grade Nickel-Based Alloy Welding Materials
Authors: Ao Ying , Xu Changzheng , He Guo , Lv Zhanpeng , Zhu Ping , Zhang Maolong , Zou Jiasheng 
Published: November 2022

Abstract
This paper mainly introduces the anti-crack performance of the nuclear grade nickel-based alloy welding materials produced by Baowu Special Metallurgy Co., Ltd. The research materials include welding wires (ERNiCrFe-7A), covered electrodes (ENiCrFe-7) and welding strips (EQNiCrFe-7A) used in PWR nuclear power plants. Evaluation of the anti-crack performance of the deposited metal is mainly carried out from the following three aspects: In order to study the thermal crack (crystal cracks) sensitivity of Baowu nickel-based alloy welding materials, the adjustable constraint test method is used and the results are compared with those of imported commercial welding materials; Based on STF (strain-to-fracture test) experimental method, the sensitivity of ductility dip cracking (DDC) of Baowu and imported nickel-based alloy welding materials is studied by thermal simulation equipment; The stress corrosion cracking (SCC) performance evaluation of Baowu welding materials is carried out by stress corrosion crack propagation experiment in simulated PWR primary water and compared with imported materials respectively. According to the above research, the crystal crack resistance, DDC resistance and SCC resistance of Baowu nickel-based alloy welding materials have reached the level of international high-level commercial welding material, which will further provide experimental data support for the engineering applicability and performance reliability of domestic nickel-based welding materials.
Classification on Electrical Parts Function Important to Safety for Nuclear Power Plants
Authors: Song Lei , He Zhijun 
Published: November 2022

Abstract
In the practice of engineering, classification of SSCs usually ends at equipment level, for example a control cabinet or switchgear based its safety function. However, classification of the parts is also necessary and meaningful. Although IAEA SSG-30 and TECDOC-1787 methodology provided is applicable to parts in equipment, safety function description of equipment usually has no direct relation to its parts, or in other word, has no strong connection. EPRI NP-5652 gives guideline on parts classification method in appendix B, but the guideline is at large.
To solve the problem, a practical classification method especially for parts is given in this paper. The method improved in this paper is based IAEA SSG-30 principle, EPRI NP-6895 and simplified FMEA. Firstly, this method take the equipment safety function classification and function description as starting; secondly, for every part in equipment, answering three main questions to determine whether the fixed part is safety related or not. Finally, the fixed part is classified as safety related or none safety related.
The practical classification method improved in this paper is not only applicable to electrical parts, but also applicable to the mechanical parts. When parent equipment’s function is not safety-related, this approach is also applicable, and then the analysis basement is equipment’s operation function.