Physics of direct-contact ultrasonic cloth drying process

Journal Article · Mon Feb 27 00:00:00 EST 2017 · Energy (Oxford)

DOI:https://doi.org/10.1016/j.energy.2017.02.138· OSTI ID:1394767

Peng, Chang ^[1]; Ravi, Saitej ^[1]; Patel, Viral K. ^[2]; Momen, Ayyoub M.  ^[2]; Moghaddam, Saeed ^[1]

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1. Univ. of Florida, Gainesville, FL (United States). Dept. of Mechanical and Aerospace Engineering
2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Building Equipment Research Energy and Transportation Science Division

Existing methods of drying fabrics involve energy-intensive thermal evaporation of moisture from clothes. Drying fabrics using high-frequency vibrations of piezoelectric transducers can substantially reduce drying time and energy consumption. In this method, vibrational energy generates instability on the liquid-air interface and mechanically ejects water from a wet fabric. For the first time, the physics of the ultrasonic fabric drying process in direct-contact mode is studied. The kinematic and thermal responses of water droplets and fabrics on piezoelectric crystal transducers and metal mesh–based transducers are studied. The results suggest that on piezoelectric crystal transducers, the response of a droplet subjected to ultrasonic excitation is dictated by the relative magnitude of the surface tension and the ultrasonic excitation forces. The drying process for a fabric on the studied transducers consists of two regimes—vibrational and thermal. When the water content is high, the vibrational forces can eject bulk water rapidly. But the more strongly bound water within the smaller fabric pores evaporates by the thermal energy generated as a result of the viscous losses. Our study finds that a metal mesh–based transducer is more suitable for dewatering fabrics, as it facilitates the ejection of water from the fabric–transducer interface to the opposite side of the mesh. A demonstration unit developed consumes 10–20% of the water latent heat energy at water contents greater than 20%.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Energy Efficiency Office. Building Technologies Office
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 1394767
• Alternate ID(s): OSTI ID: 1414798
• Journal Information: Energy (Oxford), Vol. 125, Issue C; ISSN 0360-5442
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
ultrasonic fabric dying
droplet atomization
kinematics
thermal effect