Volume 8B: Energy最新文献

{"title":"Design of a Horizontal Axis Wind Turbine for a Venusian Environment","authors":"Zacharias Garza, Kevin Pan, Anthony Izaguirre, S. Loza, Jonathan Serrano, O. López, Jim Kuo, J. Sauder","doi":"10.1115/imece2021-73558","DOIUrl":"https://doi.org/10.1115/imece2021-73558","url":null,"abstract":"\u0000 The atmosphere of Venus is 96% carbon dioxide and contains clouds of sulfur dioxide and sulfuric acid, with surface temperatures in excess of 470°C and pressures 92 times that of Earth. These extreme environmental conditions make planetary exploration difficult, as modern electronics cannot survive for prolonged periods of time. Photovoltaics, a conventional power generation method for Mars rovers, are inefficient on the planet’s surface due to the dense cloud cover and harsh environment. The NASA – JPL Hybrid Automaton Rover Venus proposes using a mechanical wind energy harvester to further explore the Venusian surface. At the proposed landing site, the surface wind speeds range from 0.3 to 1.3 m/s with an average wind speed of 0.6 m/s. These wind speeds, combined with the high density of Venusian air, results in promising potential for power generation. The power goal for the proposed wind harvester is 9W at the average wind speed of 0.6 m/s. A horizontal axis wind turbine (HAWT) is used to avoid dynamic stall experienced by vertical axis wind turbines at low wind speeds.\u0000 In the HAWT, existing airfoil profiles were evaluated and chosen using an iterative design process. The blade designs were analyzed using blade element momentum theory (BEM) to predict and improve turbine performance. Testing was performed in water, as the greater fluid density allowed for testing at a lower speed than in air to better simulate Venus surface conditions.\u0000 The preliminary water testing was carried out to characterize turbine performance. In this process, a 3D printed PLA 1:4 scale turbine was placed in an open-channel pool with flow supplied through a pump. The turbine was a fixed 2.3 m distance away from the inlet of the flow. The flow speed, turbine rotational speed, and torque produced were recorded. The results yielded turbine efficiencies between 7.7% and 46.1%. These results exceeded design expectations at the designed TSR, where an efficiency of 40% was to be expected.\u0000 Based on the preliminary results, modifications are being made to the water testbed to improve the testing process as well as more accurately simulate conditions on the surface of Venus. The collected data and the aforementioned design tools are used to improve the current turbine design.","PeriodicalId":238134,"journal":{"name":"Volume 8B: Energy","volume":"3 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":"127471547","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":"Overlap Ratio as the Design Variable for Maximizing the Efficiency of a Savonius Wind Rotor: An Optimization Approach","authors":"M. Mohan, U. Saha","doi":"10.1115/imece2021-69930","DOIUrl":"https://doi.org/10.1115/imece2021-69930","url":null,"abstract":"\u0000 The application of Savonius wind rotor is increasing worldwide to provide electricity without contributing to global warming and promoting the small-scale power production. However, its lower performance remains a major problem due to high unproductive torque produced by the returning blade. In this paper, an optimum blade profile is obtained by maximizing the power coefficient (CP) considering the overlap ratio (OR) as an optimization parameter. This is done by coupling computational fluid dynamics (CFD) simulation to the rotor blade profile developed through the simplex search method. The blade profile is symmetric about the x-axis, where half of the blade geometry is formed by a natural cubic spline curve using three points. Two end points are retained fixed, while x and y of the third point is taken as a variable in addition to OR in the simplex search process throughout its iteration using the MATLAB platform. In all the iterations, the blade profile is meshed by using ANSYS ICEM CFD platform. The rotor performance analysis is carried out by ANSYS Fluent using the shear-stress transport (SST) k-ω turbulence model. The finite volume method (FVM) is used as a solver setup to solve the transient 2D flow around the rotor blade. The optimum blade profile is compared to a conventional semicircular blade profile over a wide range of tip speed ratio (TSR). The present study demonstrates the superior performance of the optimum blade profile showing CPmax that is 23% higher than the conventional semicircular blade profile at TSR = 0.8. Further, at OR = 0.154, the CP is found to be maximum. The velocity magnitude contours, total pressure and turbulence intensity contours are generated to analyse the effect of the optimal design approach.","PeriodicalId":238134,"journal":{"name":"Volume 8B: Energy","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":"129441045","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 Analysis for a New Design of Thermal Energy Storage System","authors":"M. Elsharafi, Ali F. Elmozughi, P. Pokharel, Madison Krahl, Musaad Aldawsari, Clayton Holmes, Theo Rolle","doi":"10.1115/imece2021-67656","DOIUrl":"https://doi.org/10.1115/imece2021-67656","url":null,"abstract":"\u0000 Accumulative knowledge on Thermal Energy Storage (TES) is imperative in society today because technology is ever expanding, opening doors for improved innovation that is more sustainable to our environment. TES has a multitude of uses; from simply boiling a kettle of water on a stove to more complex applications such as solar power generation. This research focuses on the application of a thermal energy storage unit introduced to a selected Phase Change Material (PCM) to undergo controlled experimentation. It helpful to gain understanding of how the TES unit will perform in a typical laboratory environment. A PCM is any substance capable of absorbing or releasing sufficient energy to undergo a phase transition. For specified purposes of this work was, the relevant states of matter liquid and solid; hence the use of a paraffin wax was the ideal for the experimental work model where the phase transition from solid to liquid occurs in a relatively low temperature. The objective of this work was determining the amount of energy that can be stored, and the power that can be generated by using paraffin wax. The setup of the experimental work for this project was consisting of a wax chamber, corrugated steel plates, and gaskets compressed within two plexiglass frames with an inlet and outlet. Tap water was used the medium of transferring thermal energy, and a JULABO heating unit was used to generate enough thermal energy for the steel plates. PCM was used to absorb the energy and transfer it to the cold water during the PCM transformation. A normal faucet was to provide cool enough water to lower the temperature within the system initiating the liquid to solid phase transition. Hoses was used to connect the main TES unit, JULABO unit, and faucet, as well as allowing flow throughout the system. Experiential work and calculation model results shows that the energy recovery was effected by flow rates, melting temperatures, and PCM. Other factors were considered in this work including mass, volume, density, specific heat, latency, turbulence flow, Reynolds number, limitations, and factor of safety. The results of this work can be used to get useful energy especially in isolated location such as desert, ships in occasion, and military locations.","PeriodicalId":238134,"journal":{"name":"Volume 8B: Energy","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":"126088507","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}