BACKGROUND:  There is a significant need for more efficient heat transfer techniques in conversion, utilization, and recovery of energy. Traditional techniques used to enhance heat transfer rely on reducing the thermal resistance in a conventional heat exchanger by promoting higher convective heat transfer coefficients. In particular, swirl flow enhancement is popular since secondary recirculation on the axial flow in a channel can be used for single-phase as well as two-phase flows. Twisted-tape inserts are favored due to their ability to increase the heat transfer coefficient, and their ability to carry out tasks at a reduced size. However, twisted-tape inserts pay a sizeable pressure drop penalty during the process.

INNOVATION:  Researchers at UCLA have created a magnetohydrodynamic (MHD) driven swirl flow enhancement that produces a 2 to 3 time increase in the heat transfer coefficient with minimal drop in pressure. External electromagnetic power is applied directly to the liquid without any mechanical devices, and can be adjusted easily to meet specific heat exchanger needs. Heat transfer can be promoted in either a laminar or turbulent flow. All of these features provide enormous design flexibility making the proposed concept very attractive for various industrial applications, ranging from small cooling devices to vast power plant heat exchangers.

POTENTIAL APPLICATIONS 

• Industrial, Commercial, Domestic

ADVANTAGES

• Efficient heat transfer without increase in flow rate or pressure drop
• Highly compact and flexible
• Adjustable for both laminar and turbulent flow
• 2-3 fold increase in heat transfer coefficient with or without pressure drop
• Independent control of axial and azimuthal flows
• Requires minimal electromagnetic power input

DEVELOPMENT-TO-DATE:  This method has been preliminarily tested via analytical studies and computations.

Related Papers (Selected)

• Neil B. Morley, Sergey Smolentsev, Leopold Barleon, Igor R. Kirillov and Minoru Takahashi. Liquid magnetohydrodynamics recent progress and future directions for fusion. Fusion Engineering and Design. Volumes 51-52, November 2000, Pages 701-713 [more]
• N.B. Morley S. Smolentsev R. Munipalli, M.-J. Ni, D. Gao and M. Abdou. Progress on Modeling of liquid metal, free surface, MHD flows for fusion liquid walls. Fusion Engineering and Design Volume 72, Issues 1-3, November 2004, Pages 3-34 [more]

Reference: UCLA Case No. 2008-310