Revista de Engenharia Térmica最新文献_第7页

DETERMINATION OF WEIBULL PARAMETERS FOR WIND APPLICATIONS IN TWO DIFFERENT REGIONS 两个不同地区风力应用的威布尔参数测定

Revista de Engenharia Térmica Pub Date : 2018-12-28 DOI: 10.5380/RETERM.V17I2.64123

W. F. A. Borges, A. Araújo, O. D. Q. D. O. Filho, J. Rohatgi, G. F. Pinto

引用次数: 1

MATHEMATICAL MODELLING OF MACROSEGREGATION IN INGOT CASTING 铸锭铸造宏观偏析的数学建模

Revista de Engenharia Térmica Pub Date : 2018-12-28 DOI: 10.26678/ABCM.COBEM2017.COB17-2168

M. O. Junior, M. Vynnycky

引用次数: 2

AN INVERSE PROBLEM USING GREEN’S FUNCTIONS AND TFBGF METHOD TO INDENTIFICATE A MOVING HEAT SOURCE IN 3D HEAT CONDUCTION 利用格林函数和TFBGF方法求解三维热传导中运动热源的反问题

Revista de Engenharia Térmica Pub Date : 2018-12-28 DOI: 10.5380/RETERM.V17I2.64135

sidney ribeiro, G. Oliveira, G. Guimarães

引用次数: 2

NUMERICAL SIMULATION OF TEMPERATURE DISTRIBUTION ON METAL CASTING IN VERTICAL SOLIDIFICATION 金属铸件垂直凝固温度分布的数值模拟

Revista de Engenharia Térmica Pub Date : 2018-12-28 DOI: 10.26678/abcm.cobem2017.cob17-1880

E. Lins, G. Stieven, D. Soares, Edilma P. Oliveira

引用次数: 0

COMPARATIVE STUDY OF DIFFERENT MODELS FOR CALCULATION OF DNI 不同dni计算模型的比较研究

Revista de Engenharia Térmica Pub Date : 2018-12-28 DOI: 10.5380/RETERM.V17I2.64127

G. S. Lima, A. O. Souza

引用次数: 0

NUMERICAL AND EXPERIMENTAL ANALYSIS OF THE FLOW OVER A COMMERCIAL VEHICLE - PICKUP 商用车-皮卡的流动数值与实验分析

Revista de Engenharia Térmica Pub Date : 2018-12-28 DOI: 10.5380/reterm.v17i2.64136

W. J. Pinto, O. Almeida

{"title":"NUMERICAL AND EXPERIMENTAL ANALYSIS OF THE FLOW OVER A COMMERCIAL VEHICLE - PICKUP","authors":"W. J. Pinto, O. Almeida","doi":"10.5380/reterm.v17i2.64136","DOIUrl":"https://doi.org/10.5380/reterm.v17i2.64136","url":null,"abstract":"This work presents an ongoing numerical and experimental study of the flow around a pickup vehicle by means of CFD simulations and wind tunnel experiments. The model was based on the light-pickup market in Brazil and it was designed with flat surfaces and sharp edges. One of the objectives of this research was the understanding about the flow pattern around the vehicle, especially in the region behind the cabin and the wake. Another goal was to obtain original data from experimental measurements which could be used on further computational investigations. The experiments were carried out in a low-speed wind tunnel at Reynolds number of 5 x 105. Hot-wire anemometry was used to obtain the velocity profiles. Wall tufts were applied to describe the flow direction and regions of attached/detached and recirculation zones. Acceleration due to the underbody and the shear layer formed on the cabin were well defined, also indicating a region of reverse flow behind the tailgate. The flow visualization allowed the identification of recirculation regions inside the trunk and regions of detached flow. These flow patterns were also reproduced in the CFD simulations resulting satisfactory information to describe the main flow pattern over the pickup vehicle.","PeriodicalId":106768,"journal":{"name":"Revista de Engenharia Térmica","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133922851","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}

引用次数: 3

COMPARATIVE ANALYSES OF THE THERMAL PERFORMANCE OF REFRIGERANTS R134A, R245fa, R407C AND R600a DURING FLOW BOILING IN A MICROCHANNELS HEAT SINK 冷媒R134A、R245fa、R407C和R600a在微通道散热器流动沸腾过程中的热性能对比分析

Revista de Engenharia Térmica Pub Date : 2018-12-28 DOI: 10.5380/RETERM.V17I2.64132

H. L. S. L. Leão, D. Marchetto, G. Ribatski

{"title":"COMPARATIVE ANALYSES OF THE THERMAL PERFORMANCE OF REFRIGERANTS R134A, R245fa, R407C AND R600a DURING FLOW BOILING IN A MICROCHANNELS HEAT SINK","authors":"H. L. S. L. Leão, D. Marchetto, G. Ribatski","doi":"10.5380/RETERM.V17I2.64132","DOIUrl":"https://doi.org/10.5380/RETERM.V17I2.64132","url":null,"abstract":"A comparative study of the performance of of refrigerants R134a, R407C, R245fa and R600a during flow boiling was performed for a 123x494 µm2 heat sink composed of 50 parallel rectangular microchannels. Heat transfer experimental results for heat fluxes up to 310 kW/m2, mass velocities from 300 to 800 kg/(m2 s), liquid subcoolings of 5 and 10 °C and saturation temperature close to 30 ºC were obtained. Global heat transfer coefficients (footprint) up to 10 kW/(m2 °C) were found. The liquid superheating necessary for the onset of nucleate boiling (ONB) was also characterized, and the fluids R245fa and R407C presented the highest and lowest, respectively, superheating to trigger the boiling process. Moreover, for a fixed averaged vapor quality, the average effective heat transfer coefficient increases with increasing mass velocity and liquid subcooling. The refrigerants R600a and R407C presented the highest and the lowest heat transfer coefficients, respectively. Five heat transfer predictive methods from literature provided accurate predictions of the data for R134a, R245fa and R600a, capturing most of the data trends. No one method provided accurate predictions of the heat transfer coefficient data of R407C.","PeriodicalId":106768,"journal":{"name":"Revista de Engenharia Térmica","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127974898","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}

引用次数: 0

MODIFIED SERIES RESISTANCE MODEL - DETERMINATION OF MEAN CONCENTRATION BY INTEGRAL TRANSFORMATION 修正串联电阻模型——用积分变换确定平均浓度

Revista de Engenharia Térmica Pub Date : 2018-06-30 DOI: 10.5380/RETERM.V17I1.62266

A. Venezuela, R. F. Cantão, R. Ongaratto, R. Haneda

{"title":"MODIFIED SERIES RESISTANCE MODEL - DETERMINATION OF MEAN CONCENTRATION BY INTEGRAL TRANSFORMATION","authors":"A. Venezuela, R. F. Cantão, R. Ongaratto, R. Haneda","doi":"10.5380/RETERM.V17I1.62266","DOIUrl":"https://doi.org/10.5380/RETERM.V17I1.62266","url":null,"abstract":"There are several mathematical models that describe permeate flow in membrane separation processes. Among these, the series resistance model plays a prominent role. It takes into account membrane strength, concentration polarization, polarized layer and fouling to describe the permeate flow over time. In this work, an analysis of the modified series resistance model was performed, in which the resistance by polarization of the concentration is defined as being directly proportional to the transmembrane pressure. The proportionality constant is given by the product of a specific coefficient of resistance – which is determined by means of experimental data – the thickness of the boundary layer of concentration and the mean concentration. Due to the inability to obtain experimentally the value of the average concentration within the boundary layer of concentration, its simulation is carried out from the conservation equation of the chemical species. Thus, the objective of the present work was to solve the equation of the conservation of chemical species using GITT (Generalized Integral Transform Technique) and apply the modified series resistance model to describe the permeate flow of a solution of dextran through a permeable tube under laminar flow. GITT provided satisfactory results for the mean concentration, verified by comparison with the permeate flow obtained by the series resistance model with experimental results reported in the literature.","PeriodicalId":106768,"journal":{"name":"Revista de Engenharia Térmica","volume":"103 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131676529","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}

引用次数: 0

ON THE MONITORING OF THE GAS-SOLID FLOWS IN INDUSTRIAL FLUIDIZED BEDS BY USING ELECTRICAL CHARGE SENSORS 用电荷传感器监测工业流化床气固流动的研究

Revista de Engenharia Térmica Pub Date : 2018-06-30 DOI: 10.26678/abcm.cobem2017.cob17-1715

E. Reis, Matheus Ferreira Felix de Andrade

{"title":"ON THE MONITORING OF THE GAS-SOLID FLOWS IN INDUSTRIAL FLUIDIZED BEDS BY USING ELECTRICAL CHARGE SENSORS","authors":"E. Reis, Matheus Ferreira Felix de Andrade","doi":"10.26678/abcm.cobem2017.cob17-1715","DOIUrl":"https://doi.org/10.26678/abcm.cobem2017.cob17-1715","url":null,"abstract":"The fluidized bed technology has been used in many industrial processes. It promotes good rates of heat, mass transfer and chemical reaction by generating high level of gas-solid mixture. However, the assurance of quality and efficiency of these processes requires the monitoring of the gas-solid flow. For this propose, there are some sensing techniques that allows generating dynamic signals from cold or hot fluidized beds. They are based on pressure fluctuations, acoustic and mechanical vibrations, electrical capacitance and on electrical charges. Electrical charge sensors were proposed originally for measuring the flow velocity in pneumatic conveying. They are composed of one or more metallic electrodes that detect electrical charges in the gas-solid flow, which are generated by particle-particle and particle-wall interaction due to triboelectric effect. In this work, such sensors are explored as a robust and inexpensive solution for the monitoring of industrial fluidized beds. However, since research investments are requested specially on the design of the sensor, concerning the flow quantity of interest and the electrification processes acting on the sensor, in this work different configurations were classified from information in literature, and other were proposed in this work concerning their use with industrial fluidized beds. Although the relation between magnitude of the detected charges and some physical quantities of the flow, such as concentration, is still not clear, other important information can be obtained by analyzing dynamic signals, as velocity or bubbles frequency, or even for identifying of the fluidization regime. It was stated that each configuration, with its own shape and arrangement, can promote or not one or other electrification process by contact, friction or induction and, therefore, each one has a different perception of the flow.","PeriodicalId":106768,"journal":{"name":"Revista de Engenharia Térmica","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115478060","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}

引用次数: 1

NUMERICAL SIMULATION OF A ELASTO-VISCOPLASTIC FLUID FLOW INSIDE A CAVITY 弹粘塑性流体在空腔内流动的数值模拟

Revista de Engenharia Térmica Pub Date : 2018-06-30 DOI: 10.5380/RETERM.V17I1.62262

Giovanni M. Furtado, S. Frey, M. Naccache, P. Mendes

引用次数: 0