Fan Performance Characteristics at Various Rotational Speeds and Ambient Pressures

Wu, Wei; Lin, Youxi; Chow, L. C.; Leland, Quinn

doi:10.4271/2014-01-2219

Cited by 11 publications

(8 citation statements)

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“…Scaling laws can be used to predict the fan performance under different speeds and ambient pressures [7]. Although fans may not be reliable enough for cooling aircraft EMAs, it was found that using dual-fans can reduce the failure probability in one hour of flight from 10 -5 to 10 -9 without adding heavy weight and high cost [8].…”

Section: Hydraulic Losses Estimatementioning

confidence: 99%

Design and Testing of a Cooling Fan for Electro-Mechanical Actuators for Aerospace Applications

Wu¹,

Yr²,

Mesalhy³

et al. 2017

Int J Astronaut Aeronautical Eng

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can remove waste heat from the aircraft EMAs components and transport the heat to the entire bay surfaces. The entire bay surfaces area can act as a heat sink, thus avoiding the need to mount a condenser or cold plate to the bay wall. The EMAs waste heat is generated at the motor, associated control electronics (E-box), gear box, and drive train. The major heat generation source is the motor and it has fins and a cooling fan attached. The fan is structurally integrated with the motor, but is powered and controlled independently with temperature sensors so that the fan is turned on whenever a certain temperature of the actuator is exceeded [2,3]. The drive train and gear box are cooled by recirculating air within the bay. Enclosing the fins with an outer shell creates an annular duct for air to pass through. This way the forced

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Section: Hydraulic Losses Estimatementioning

confidence: 99%

Design and Testing of a Cooling Fan for Electro-Mechanical Actuators for Aerospace Applications

Wu¹,

Yr²,

Mesalhy³

et al. 2017

Int J Astronaut Aeronautical Eng

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“…Researchers have currently conducted studies of these harsh changes in the environment on fan performance. [4][5][6][7][8][9][10] Corona et al, 4 Wu et al, 9 fan scaling laws were tested and demonstrated to accurately predict fan performance based upon scaling of fan speed, density, and power input except for the low pressure (0.2 atm) condition. Reliability increase based upon multiple similar fans has been conducted to ensure proper cooling to the electric motors in EMAs.…”

Section: Introductionmentioning

confidence: 99%

“…24 To the best of the authors' knowledge, the work before the current work has not been conducted to this extent. The work presented is an extension of the work that has been conducted [4][5][6][7]9,25,26 with an emphasis on analyzing the best efficiency points of the fan at various fan rotational speeds, ambient pressure conditions, blade count, and the effect of interchanging the preexisting design with an airfoil. The current work can be used as a basis for considering the best operating condition of fan efficiency based upon the parameters presented in this study.…”

Section: Introductionmentioning

confidence: 99%

The best efficiency point of an axial fan at low-pressure conditions

Corona

Mesalhy

Chow

et al. 2021

Advances in Mechanical Engineering

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In the current work, the objective is to determine the best efficiency point (BEP) of an axial fan using CFD. Analyzing the performance of the fan based upon the parameters chosen can lead to the optimal design of an axial flow fan for aerospace applications where the ambient pressure varies rapidly. The 2-bladed fan chosen for the study is the Propimax 2L which is considered the base fan used for comparison of all the results of the work. The set of parameters tested were fan rotational speed, ambient pressure conditions, blade count, and the airfoil design. All the performance measures were based on overall fan efficiency. The results yield the following: an increased rotational speed led to higher efficiencies, the most efficient ambient pressure of which the fan can perform is 0.7 atm, a 5-bladed fan configuration produced the highest efficiency, and airfoil selection is critical for fan efficiency enhancements. The results demonstrated that at 0.7 atm the fan efficiency is the highest due to the changes in power consumption to the density effect. A key finding in the work is that higher blade counts do not necessarily lead to higher performing axial fans. A high cambered airfoil provided a higher flow rate at free delivery than that of the Propimax 2L design, but the rotorcraft airfoil did not yield favorable results. The analysis is focused on the fan design of cooling of the electromechanical actuators (EMAs).

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“…Therefore, in order to accurately characterize the fans capability at low densities, fan curves were needed for its operation at reduced pressure. Work done by Lin[14], at the University of Central Florida, directly contributed to characterizing this fan at reduced pressures. Lin gathered experimental data on the performance of the Propimax 2L fan and constructed fan curves for pressures at 1.0 atm, 0.7 atm, 0.5 atm and 0.2 atm.…”

mentioning

confidence: 99%

“…The velocity is derived from dynamic pressure ( , measured at the Pitot tube, shown in the following equation.Equation 3In order to find the pressure drop within the wind tunnel both the density of the air and velocity had to be known. This was achieved by plotting the wind tunnel system resistance against the fan curves[14] at various ambient pressures (i.e., air densities), shown in Figure 3.11, Figure 3.12, Figure 3.13, and Figure 3.14. The intersection of the system resistance and fan flow rate were found.…”

mentioning

confidence: 99%

Experimental StudyHigh Altitude Forced Convective Cooling of Electromechanical Actuation Systems

Racine

2016

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The evaluation of the effects of altitude on forced air convective cooling is studied experimentally. The evolution of the more electric aircraft has led to the adoption of high power electronics for flight critical systems and the need to mitigate their thermal loads. Changes in altitude affect properties that govern heat transfer, such as air pressure, density, and temperature. Current methodology behind heat transfer prediction lacks a comprehensive experimental validation at altitudes above 16,000 feet, relevant to commercial and military aircraft. The convective heat transfer coefficient at altitudes from 0 to 52,000 feet above sea level at sea level room temperature (~24°C) was measured through the use of a wind tunnel inside a vacuum chamber. Test results, with Reynolds number ranging from 500 to 14,000 and pressure from 0.1 atm to 1.0 atm, confirm that the Nusselt number and pressure loss coefficient are independent of altitude and can be determined from experimental measurement, numerical simulation, and suitable correlations obtained at sea level. Both quantities are functions of Reynolds number only. This experimental investigation will serve to provide a greater confidence iv for predictive methods of heat transfer at high altitude, which can lead to better optimized thermal management solutions for flight control electromechanical actuation systems. v ACKNOWLEDGEMENTS The completion of my master's thesis has required a lot of hard work. However, it would not have been possible without the support and guidance of advisors, coworkers, friends, and family. I would like to take the time to thank those individuals. I would first like to thank my family for always supporting me with my pursuits in my professional and educational careers. Without their advice and support I would not have been able to reach goals that I have. Next, I would like to thank my advisor Quinn Leland who provided me with the opportunity of a research assistantship through the Air Force Research Laboratory and whose valuable guidance led to the success of this project. I would like to thank Louis Chow from University of Central Florida. Without his technical expertise and guidance this project would not have been possible. I would also like to thank my advisor Jamie Ervin who originally referred me to the opportunity at the AFRL and who has been very helpful with the completion of this work. I would also like to thank all the individuals from the UDRI, AFRL and UCF who contributed advise, support and guidance along the journey of this thesis; my supervisor Bang Tsao from the University of Dayton Research Institute, as well as my other colleagues from UDRI, Steve Fuchs, John Murphy and Street Barnett. I would like to thank my interns, Paul Fuchs and Zach Adamson who were instrumental with vi construction and testing of this experiment. My gratitude also goes to Yeong-Ren Lin from UCF who provided valuable insight into designing this experiment. I would also like to thank Justin Delmar and Mike Bruggeman from the AFRL who each uniquel...

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Fan Performance Characteristics at Various Rotational Speeds and Ambient Pressures

Cited by 11 publications

References 0 publications

Design and Testing of a Cooling Fan for Electro-Mechanical Actuators for Aerospace Applications

Design and Testing of a Cooling Fan for Electro-Mechanical Actuators for Aerospace Applications

The best efficiency point of an axial fan at low-pressure conditions

Experimental StudyHigh Altitude Forced Convective Cooling of Electromechanical Actuation Systems

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