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Steady State Mathematical Modeling of Non-Conventional Loop Heat Pipes: A Parametric and a Design Approach

Remella Siva Rama, Karthik
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1353154991

Abstract Details

2012, MS, University of Cincinnati, Engineering and Applied Science: Mechanical Engineering.
A Non-Conventional Loop Heat Pipe, much different from a conventional LHP, is employed in cooling Light Emitting Diode luminaries in high bay lighting. Different from a conventional LHP, these devices use the entrainment phenomenon to passively transport waste thermal energy dissipated from the LEDs into ambient air. Unlike a conventional LHP, the pressure drop across the liquid-vapor interface in the evaporator wick is not very high. In the present work, two different mathematical models – a parametric model and a design model, are developed. The device is partitioned into three prominent sections – the evaporator, the condenser and the sub-cooler. Each of these sections is individually studied, understood, and modeled. The data collected from the experiments performed on the non-conventional LHP are utilized in formulating some empirical coefficients for these models such as the convection heat transfer coefficient for the ambient air, a few thermal resistances in the evaporator package and a constant temperature difference between the bulk fluid and the walls of the tube in the sub-cooler section of the device. An attempt to mathematically model the non-conventional LHP provides some insights into the relationship of the nature of working fluid with the quality of the two-phase mixture, and the mass flow rate. The parametric model throws light on the various parameters that are necessary for the LHP to successfully remove a certain amount of thermal energy from the LEDs. Different parameters that could potentially increase the temperature of the board are studied and delineated in this work. The design model illustrates a method for estimating the geometry of the device for cooling a specific LED power for a particular application. The attempt to model the current device is a first step in trying to design a product capable of cooling a 1000 W equivalent LED fixture. Additionally, these models could potentially lay the foundation for understanding the relationship between the mass flow rate, the quality of the working fluid entering the condenser due to entrainment, the pressure drop across the interface and the amount of latent energy lost in the condenser of this device.
Frank Gerner, Ph.D. (Committee Chair)
Ahmed Shuja, Ph.D. (Committee Member)
Milind Jog, Ph.D. (Committee Member)
170 p.
Mechanical Engineering
Entrainment; Loop Heat Pipe; LED cooling; Parametric model; Design model;

Recommended Citations

Citations

  • Remella Siva Rama, K. (2012). Steady State Mathematical Modeling of Non-Conventional Loop Heat Pipes: A Parametric and a Design Approach [Master's thesis, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1353154991

    APA Style (7th edition)

  • Remella Siva Rama, Karthik. Steady State Mathematical Modeling of Non-Conventional Loop Heat Pipes: A Parametric and a Design Approach. 2012. University of Cincinnati, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1353154991.

    MLA Style (8th edition)

  • Remella Siva Rama, Karthik. "Steady State Mathematical Modeling of Non-Conventional Loop Heat Pipes: A Parametric and a Design Approach." Master's thesis, University of Cincinnati, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1353154991

    Chicago Manual of Style (17th edition)

ucin1353154991
553
© 2012, all rights reserved.
This open access ETD is published by University of Cincinnati and OhioLINK.