Convective heat transfer coefficients evaluation for a portable forced air tunnel

Barbin, Douglas Fernandes; Filho, Lincoln C. Neves; Júnior, Vivaldo Silveira

doi:10.1016/j.applthermaleng.2009.08.009

Cited by 17 publications

(5 citation statements)

References 8 publications

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“…The validity of this hypothesis was demonstrated in a previous study for the range of Nusselt numbers of this application, because Biot number (Bi) ranges between 0.0007 and 0.004 [29]. When Biot number is below 0.01 temperature gradients inside the object can be definitively neglected because heat conduction is indeed much faster than the heat convected away from its surface [30].…”

Section: The 1d Numerical Modelmentioning

confidence: 64%

Design and manufacture of a high-temperature PEMFC and its cooling system to power a lightweight UAV for a high altitude mission

Renau

Barroso

Lozano

et al. 2016

International Journal of Hydrogen Energy

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In the present study, the optimal design of a high-temperature proton exchange membrane fuel cell (HT-PEMFC) that will be used to power an unmanned aerial vehicle (UAV) in a high altitude mission is performed. The use of PEMFCs for service ceiling above 10 km implies overcoming a number of problems caused by the harsh environmental conditions. Among them, new strategies to manage the heat generated by electrochemical reactions are needed. The maximum power required by the UAV was determined solving the aerodynamic problem, and the design of the lightweight HT-PEMFC, including its cooling system, was optimized. To perform the numerical solution of the heat transfer problem, a computational code was implemented using the EES software. The decisions adopted resulted in a 40-cells stack with an electric power above 1 kW and a weight around 3.65 kg. Besides, it is demonstrated that, for the configuration considered in the study, a passive cooling system without any additional fan system can be used to maintain the stack temperature in 160°C.

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Section: The 1d Numerical Modelmentioning

confidence: 64%

Design and manufacture of a high-temperature PEMFC and its cooling system to power a lightweight UAV for a high altitude mission

Renau

Barroso

Lozano

et al. 2016

International Journal of Hydrogen Energy

View full text Add to dashboard Cite

show abstract

“…For the experimental conditions and materials of the present research, the Biot number ranges from 0.0007 to 0.004. As the Bi number is well below 0.01, temperature gradients inside the object can be neglected because heat conduction is indeed much faster than heat convection away from its surface [50]. It is then reasonable to assume that temperature and heat transfer are constant throughout the object.…”

Section: Resultsmentioning

confidence: 99%

Experimental determination of the heat transfer coefficient for the optimal design of the cooling system of a PEM fuel cell placed inside the fuselage of an UAV

Barroso

Renau

Lozano

et al. 2015

Applied Thermal Engineering

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h i g h l i g h t sHeat transfer coefficients to refrigerate a HT-PEMFC stack are calculated. Experiments are performed in 2 wind tunnels, for 3 form factors and real conditions. The calculated heat transfer coefficient varies from 8 to 44 W m À2 K À1 . Results at sea level are suitably extrapolated for a target altitude of 10 km. Flow area is optimized as a function of the power required to cool the stack down. a b s t r a c tThe objective of this research is to calculate the heat transfer coefficients needed for the further design of the optimal cooling system of a high-temperature polymer electrolyte membrane fuel cell (HT-PEMFC) stack that will be incorporated to the powerplant of a light unmanned aerial vehicle (UAV) capable of reaching an altitude of 10,000 m. Experiments are performed in two rectangular tunnels, for three different form factors, in experimental conditions as close as possible to the actual ones in the HT-PEMFC stack. For the calculations, all the relevant thermal processes are considered (i.e., convection and radiation). Different parameters are measured, such as air mass flow rate, inlet and outlet air temperatures, and wall temperatures for bipolar plates and endplates. Different numerical models are fitted revealing the influence of the diverse relevant non-dimensional groups on the Nusselt number. Heat transfer coefficients calculated for the air cooling flow vary from 8 to 44 W m À2 K À1 . Results obtained at sea level are extrapolated for a flight ceiling of 10 km. The flow section is optimized as a function of the power required to cool the stack down to the temperature recommended by the membrane-electrode assembly (MEA) manufacturer using a numerical code specifically developed for this purpose.

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“…En los modelos superficiales cerrados [6] [7], "cuadrilátero-dominante" (4 nodos) los elementos de cáscara (SHELL 181), se utilizan proporcionando exactitud y eficacia mientras que son convenientes para los algoritmos de mallado automático robusto usados en la simulación WORKBENCH. Y, para la interacción de las partes dentro de un ensamblaje, se utilizan los elementos de contacto (CONTACT 170/174).…”

Section: Celementosunclassified

Thermal-mechanical analysis of the briquetting machine segments in steel industries

Jaimes

2020

mrv

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A thermal-mechanical analysis of the behavior of the segments of the rollers of the briquetting machines is carried out due to the effect of thermal shock and efforts exerted on the part. It is intended to obtain the main causes that generate this problem, through a mechanical analysis that simulated the behavior in the presence of several thermal gradients. The purpose of the study is to reduce maintenance costs and the continuous replacement and repair of segments, as well as losses in tons of production due to the failure that are of great impact to the industry. This investigation allows us to know to what extent the operating parameters, such as: material temperature, pressure, torque, speed of the rollers influence the life of the segments according to their manufacturing material and based on these the behavior is simulated during the briquetting process. Keywords: Simulation, Finite element, Briquettes. [1]D. F. Pinzón, «Diseño óptimo de Sistemas de Distribución,» Universidad Nacional de Colombia, Bogotá, 2014. [2]F. A. Mendoza Lameda, «Diseño multiobjetivo y multietapa de sistemas de distribución de energía eléctrica aplicando algoritmos evolutivos,» Universidad de Zaragoza, Zaragoza, 2010. [3]L. Miró Hernández y R. Vizcón Toledo, «Sistema Hibrido Propuesto Para la Generación de Electricidad en un Policlínico,» Revista Avanzada Científica, vol. 9, nº 2, pp. 50-56, 2006. [4]J. Lagunas M., C. Ortega S. y P. Caratozzolo M., «Control supervisorio para sistemas híbridos de geración eléctrica basado en lógica difusa,» Boletin UE, Monterrey, 2005. [5]J. L. Bernal Agustín, «Aplicación de algoritmos genéticos al diseño óptimo de sistemas de distribución de energía eléctrica,» Universidad de Zaragoza, Zaragoza, 1998. [6]V. MIranda, J. V. Ranito y L. Proenca, «Genetic Algorithms in Optimal Multistage Distribution Network Planning, » IEEE, Porto, 1994. [7]I. Ramirez-Rosado y J. Dominguez-Navarro, «Computer Aided Desing of Power Distribution Systems: Multiobjective Mathematical Simulations» International Journal of Power and Energy Systems, vol. 19, nº 4, pp. 1801-1810, 2004.

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Convective heat transfer coefficients evaluation for a portable forced air tunnel

Cited by 17 publications

References 8 publications

Design and manufacture of a high-temperature PEMFC and its cooling system to power a lightweight UAV for a high altitude mission

Design and manufacture of a high-temperature PEMFC and its cooling system to power a lightweight UAV for a high altitude mission

Experimental determination of the heat transfer coefficient for the optimal design of the cooling system of a PEM fuel cell placed inside the fuselage of an UAV

Thermal-mechanical analysis of the briquetting machine segments in steel industries

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