Volume 10: Fluids Engineering最新文献

{"title":"Critical Shear Stress for Erosion Under Laminar Jet Flow","authors":"L. Pease, J. Bamberger, M. Minette","doi":"10.1115/imece2021-67639","DOIUrl":"https://doi.org/10.1115/imece2021-67639","url":null,"abstract":"\u0000 Here we evaluate critical shear stresses for erosion under laminar jet flow. To date critical shear stresses for erosion, as embodied in Shields diagrams, have largely been developed for turbulent flow both experimentally and mathematically. However, curves on the Shields diagrams diverge among various models at lower particle Reynolds numbers. Indeed, how critical shear stresses for erosion develop under fully laminar jet flow conditions (not simply laminar boundary layers under turbulent flow) remains unclear. Here we address this gap, which is particularly important for mobilization of the smallest particles. We find the Shields parameter to be inversely proportional to the particle Reynolds numbers under laminar jet flow conditions similar to turbulent conditions.","PeriodicalId":112698,"journal":{"name":"Volume 10: Fluids Engineering","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124783221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Numerical Study of the Effect of Surface Coverage on the Filtration Performance of Hair Arrays","authors":"S. Tanikella, Nathan D. Jones, E. Dressaire","doi":"10.1115/imece2021-69668","DOIUrl":"https://doi.org/10.1115/imece2021-69668","url":null,"abstract":"\u0000 Biological filtration systems offer a sustainable alternative to existing engineered solutions. In this computational work, we seek to optimize the surface coverage by an array of hairs to capture particles in channels. A variety of aquatic organisms rely on arrays of hairs to interact with their fluidic environments. The hair functionality can vary from sensing to smelling, filtration to flow control depending on the species considered. Among those organisms are filter-feeders that rely on suspension-feeding, one of the most widespread feeding mechanisms and one of the oldest. Baleen whales are filter-feeders that catch their prey by using the baleen, a complex structure composed of plates and bristles in their mouth. The hairs are hollow cylindrical structures with a diameter of a few hundred micrometers that can extend over tens of centimeters. The baleen filters out the prey while letting the seawater through. The baleen is composed of flexible and elongated structures whose properties fit the feeding habits of the whale.\u0000 The porosity of the structure depends on the flow feature. Effectively, the flow can tune the filter properties, which sets biological filters apart from their engineered counterpart. Previous mechanical studies have shown that an array of hairs can either act as a sieve, allowing all the fluid to flow through it, or as a rake, forcing the fluid to flow around it instead. As the speed increases, the behavior shifts from rake to sieving for a given hair spacing. From a filtration perspective, the rake regime is not favorable as particles do not enter the array. For a fixed fluid velocity, the flow transitions from rake to sieve as the spacing between the hairs in the array increases. Our recent work has also demonstrated that the confinement of the channel influences the sieve to rake transition. The filtration mechanisms that filter-feeder organisms use to capture food particles exhibit complex fluid-structure interactions that have yet to be leveraged in engineered systems. To guide the development of hair-covered surfaces capable of trapping particles in channel flows, we investigate how different geometric factors affect the fluid transport and capture of particles by the array. In previous work, a small number of hairs, typically 25, were considered. Here, we vary the array geometry, the Reynolds number of the flow, and the surface coverage to study the transport through this confined porous structure. We compare arrays based on their optimal efficiency and the (sub-optimal) operating conditions which make the filter versatile.","PeriodicalId":112698,"journal":{"name":"Volume 10: Fluids Engineering","volume":"46 14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124642330","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Hemispherical Protuberance on the Leading-Edge to Control the Laminar Separation Bubble","authors":"Pradeep Singh, S. Sarkar","doi":"10.1115/imece2021-73068","DOIUrl":"https://doi.org/10.1115/imece2021-73068","url":null,"abstract":"\u0000 The excitation of a laminar separation bubble (LSB) under the influence of a hemispherical protuberance has been discussed here. The experiments were conducted over a modeled aerofoil of constant thickness with a semi-circular leading-edge at a Reynolds number (Re) of 1.6 × 105, where freestream turbulence (fst) is 1.2%. A protuberance of height, k = 3 mm is placed at an angle of 60 from the theoretical stagnation point. The characteristic Re based on the diameter of the element and freestream velocity is 1442. The protuberance sheds streamwise vortices leading to an unsteady flow near the leading edge, resulting in a reduction of bubble length by 31–78%. Further, the separation bubble length, its fundamental shedding frequency, and the turbulence statistics become highly asymmetric in the spanwise direction, while the influence of protuberance is felt up to 6k.","PeriodicalId":112698,"journal":{"name":"Volume 10: Fluids Engineering","volume":"195 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120979601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Profile Loss of a Printed Transonic Turbine Cascade","authors":"L. Hake, S. aus der Wiesche","doi":"10.1115/imece2021-70215","DOIUrl":"https://doi.org/10.1115/imece2021-70215","url":null,"abstract":"\u0000 Profile losses of turbine blades are one of the main problems in turbine technology. Besides the occurring aerodynamic effects, it is well known that the surface roughness has a significant influence on these losses. It is generally known that a better surface quality leads to lower profile losses. Many studies for this topic are given in open-source literature, but the investigations were mainly performed in an ideal gas atmosphere (air). The present contribution presents the results of an experimental study of profile losses of an additive manufactured linear turbine cascade placed in the test section of a closed-loop organic vapor wind tunnel, or CLOWT for short. The investigations are carried out under an organic superheated steam atmosphere. For this organic vapor atmosphere, the of carbon based liquid Novec™ 649 has been used. In addition, measurements were also realized in an air atmosphere. To get different point of views, three different approaches are chosen to determine the profile losses.","PeriodicalId":112698,"journal":{"name":"Volume 10: Fluids Engineering","volume":"230 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116429389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Validation Study of Reynolds Stress Model Coupled With Gamma Transition for UAV Propellers","authors":"Naina Pisharoti, S. Brizzolara","doi":"10.1115/imece2021-70674","DOIUrl":"https://doi.org/10.1115/imece2021-70674","url":null,"abstract":"\u0000 The current study is carried out to investigate complex near-wall flow effects like separation and cross-flow and their impact on UAV performance. Furthermore, the study proposes using the novel SSG/LRR-ω-γ model, which is a second-order closure, Reynolds stress transport-based transition turbulence model, that can help capture the near-wall flow observed in low Reynolds number flows. To prove the credibility of the model, it is validated against experimental data available for the DJI Phantom 3 propeller. The SSG/LRR-ω-γ model is then compared against other transition models as well as fully turbulent models and was found to show better performance when assessed on their ability to predict rotor performance characteristics as well as near-wall flow behavior.","PeriodicalId":112698,"journal":{"name":"Volume 10: Fluids Engineering","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133423326","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Helium Degassing Filter for Mercury Process Gas Liquid Separator","authors":"J. Weinmeister, Dustin Ottinger, C. Barbier","doi":"10.1115/imece2021-72699","DOIUrl":"https://doi.org/10.1115/imece2021-72699","url":null,"abstract":"\u0000 Testing was conducted to find a suitable filter to help separate helium gas from the Spallation Neutron Source’s mercury process loop. This filter is proposed for installation on the gas-liquid separator (GLS) vent line to prevent a column of liquid mercury from flowing outside of the process loop shielding in the service bay. The filter’s desired properties are to prevent the passage of liquid mercury, provide minimal resistance to helium flow, resist radiation, operate for the lifetime of the target, be replaceable, and have a reliable construction. Testing concluded that the Mott Corporation POU-10-S series of filters provided the best performance available. The filters could stop most liquid mercury passage while allowing helium passage at nominal pressures above the GLS in standard conditions. This result has several implications for the design of the GLS vent system.","PeriodicalId":112698,"journal":{"name":"Volume 10: Fluids Engineering","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132786301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Verification Study of CFD Prediction Accuracy of Liquid Droplet Impingement Erosion Rate for Engineering Applications","authors":"Shaoxiang Qian, Xidong Hu, Shinichiro Kanamaru","doi":"10.1115/imece2021-70977","DOIUrl":"https://doi.org/10.1115/imece2021-70977","url":null,"abstract":"\u0000 Multi-phase flows containing liquid droplets widely exist in piping system of process plants. Sudden geometry change like elbow causes the flow turbulence, which leads to droplet impingement against the piping wall. As a result, erosion can be induced, and hence, may cause leak of piping. Therefore, it is essential to evaluate erosion rate for determining design margin and finding countermeasures for erosion-related trouble. Some models have been proposed for predicting droplet-induced erosion rate, but there is large difference in their prediction accuracy. The present study aims at verifying prediction accuracy of some major erosion models for engineering applications.\u0000 CFD simulations of water jets are conducted to verify the prediction accuracy of erosion induced by liquid droplets, using the published experimental data. In the present simulations, a two-way approach is applied for solving the air-water two-phase flow. An original algorithm is used to calculate the droplet-induced erosion rate using the obtained two-phase flow fields. The investigated erosion models include the models of Haugen, DNV and Isomoto. CFD results show that almost all the investigated erosion models for various simulation conditions provide the conservative evaluation of erosion rates, compared with the experimental results. Among them, the erosion rates predicted by Haugen model are closest to the experimental results with acceptable prediction accuracy for engineering applications.","PeriodicalId":112698,"journal":{"name":"Volume 10: Fluids Engineering","volume":"84 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132806042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental Investigation of High-Speed Flows Past Pillow Plates","authors":"S. Sundermeier, S. aus der Wiesche","doi":"10.1115/imece2021-70223","DOIUrl":"https://doi.org/10.1115/imece2021-70223","url":null,"abstract":"\u0000 This paper presents an experimental investigation of highspeed flows past Pillow-Plate Heat Exchanger (PPHE) geometries by means of conventional and focussing schlieren optics. Past investigations have already shown that PPHE has positive flow behaviours compared to other heat exchangers. The static pressure drop along a pillow-plate surface is relatively low, but the profile offers a good mixing and heat transfer behaviour. These characteristics were not very well researched for higher Mach numbers until now.","PeriodicalId":112698,"journal":{"name":"Volume 10: Fluids Engineering","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130145627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fluid-Structure Interaction of Slender Biofilaments at Low Reynolds Numbers","authors":"Mehrad Mortazavi, V. Ayyaswamy, A. Gopinath, Sachin Goyal","doi":"10.1115/imece2021-70702","DOIUrl":"https://doi.org/10.1115/imece2021-70702","url":null,"abstract":"\u0000 Active filamentous organelles such as cilia and flagella oscillate due to the interplay between activity, elasticity, and viscous hydrodynamic drag. The presence of no-slip boundaries also impacts the viscous drag forces on the filament. Recent efforts to develop low Reynolds numbers synthetic swimmers and mixers that mimic the ciliary dynamics have used effective elastic filaments that are animated. The instabilities underlying the spatiotemporal dynamics of such biomimetic filaments are dominated equally by elasticity and fluid-solid viscous interactions. Predicting ensuing patterns requires robust computational models that can capture both large-amplitude elastic deformation of the filaments and associated long-ranged hydrodynamic interactions. To address this coupled elastohydrodynamic problem, we develop a composite framework that combines a computational rod model valid for slender filaments and slender body theory (SBT) that accounts for hydrodynamic interactions. The presence of no-slip boundaries is accounted for by using a wall-corrected slender body theory (W-SBT). We analyze the accuracy of the slender body formulations and compare them to solutions obtained via computational fluid dynamic solvers. SBT and W-SBT are found to be computationally faster than other hydrodynamic models; however, they may not provide accurate solutions for small aspect ratio filaments. The fluid-structure interaction model we present here, provides a starting point to computationally investigate the movements of natural and biomimetic cilia and flagella in the vicinity of plane walls.","PeriodicalId":112698,"journal":{"name":"Volume 10: Fluids Engineering","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132857599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical Study of Deformation of Viscoelastic Drop Migrating Through Microchannel With Sudden Constriction","authors":"N. Prasad, Siddhartha Sankar Ghosh, A. Dalal","doi":"10.1115/imece2021-71401","DOIUrl":"https://doi.org/10.1115/imece2021-71401","url":null,"abstract":"\u0000 In this paper, deformation of viscoelastic drop in a microscale flow with sudden constriction is studied numerically. . The effect of polymeric viscosity on deformation of viscoelastic fluid is studied for two different solvent viscosity ratio and two different channel confinement in two-phase viscoelastic drop-Newtonian matrix system. The Finitely Extensible Non-linear Elastic–Peterlin (FENE-P) model was used to model the viscoelastic drop. The simulation was performed using open source solver Basilisk. The viscoelastic drop with lower polymeric viscosity and higher solvent viscosity seemed to undergo appreciable deformation inside constricted microchannel when subjected to sudden contraction. The low polymeric viscosity of a viscoelastic fluid corresponds to a dilute polymeric solution, its viscoelastic behavior is best explained by seeing its deformation under high shear flows inside microchannel. The isolated arrangement of polymeric coils in dilute polymeric solutions assists independent molecular movement, which supports their deformation under high shear flows. The FENE-P drop model used in the present study, at higher solvent viscosity, exhibit faster stress relaxation and remarkable elastic recovery in the expansion zone of the microchannel. The dilute FENE-P viscoelastic fluid can also be considered as a significant model to predict the viscoelastic behavior of useful polymeric fluids like hydrogels, paints, and vesicles, etc.","PeriodicalId":112698,"journal":{"name":"Volume 10: Fluids Engineering","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129333584","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}