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20130320_Oliver_Dissertation_Final.pdf (4.13 MB)

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A STUDY ON THE PHYSICS OF ICE ACCRETION IN A TURBOFAN ENGINE ENVIRONMENT

Oliver, Michael James
http://rave.ohiolink.edu/etdc/view?acc_num=case1363875844

Abstract Details

2013, Doctor of Philosophy, Case Western Reserve University, EMC - Mechanical Engineering.
Numerous turbofan engine loss of thrust control events have led to a theory that ice is accreting on initially warmer than freezing internal engine hardware and affecting normal operation. The phenomenon is termed ice crystal icing. Previous ice crystal icing research on a simple airfoil empirically identified the effects of pressure, temperature and relative humidity on the equilibrium surface temperature and the characteristic ice that accretes. In these cases with freezing fraction and impinging particle temperature as experimental unknowns, the on-set of ice accretion on an initially warmer than freezing surface was found to correlate with a below freezing thermodynamic wet-bulb temperature. In the present work, a novel ice accretion model, based on a modified Tribus-Messinger (MTM) surface energy balance, is developed. Implementing the model, the effect on the equilibrium surface temperature and freezing fraction near the leading edge stagnation region of an airfoil operating in icing conditions is investigated by varying the parameters of ambient static pressure, ambient static temperature, relative humidity and impinging particle temperature. The previously identified effects of pressure, temperature and relative humidity are identified as well as a new impinging particle temperature effect. A below freezing adiabatic saturation temperature, analogous to the thermodynamic wet-bulb temperature is calculated and shown to correlate with the predicted onset of ice accretion. Implementing the MTM model to investigate the physics of the modified surface energy balance, the pressure, temperature, relative humidity and impinging particle temperature effects are shown to be coupled within the latent, convective and sensible energy terms of the modified balance. The model predicts the observed onset of accretion and characteristic ice that forms on the surface from two experimental test cases. Control of the onset of ice accretion for these cases is demonstrated by varying the inputs to the model. It is also shown that by changing the impinging particle temperature for a given test condition the onset and characteristic ice that accretes can be influenced and predicted. Since particle temperature influences the surface temperature the wet-bulb temperature alone may not always predict the onset of ice accretion.
Joseph Prahl (Committee Chair)
171 p.
Aerospace Engineering; Engineering; Mechanical Engineering; Physics
ice crystal icing; turbofan engine inclement weather operation; appendix D; loss of thrust control; physics of ice accretion in a turbofan engine environment

Recommended Citations

Citations

  • Oliver, M. J. (2013). A STUDY ON THE PHYSICS OF ICE ACCRETION IN A TURBOFAN ENGINE ENVIRONMENT [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1363875844

    APA Style (7th edition)

  • Oliver, Michael. A STUDY ON THE PHYSICS OF ICE ACCRETION IN A TURBOFAN ENGINE ENVIRONMENT. 2013. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1363875844.

    MLA Style (8th edition)

  • Oliver, Michael. "A STUDY ON THE PHYSICS OF ICE ACCRETION IN A TURBOFAN ENGINE ENVIRONMENT." Doctoral dissertation, Case Western Reserve University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=case1363875844

    Chicago Manual of Style (17th edition)

case1363875844
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© 2013, all rights reserved.
This open access ETD is published by Case Western Reserve University School of Graduate Studies and OhioLINK.