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6371 |
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Wednesday, June 10, 2020, Hall D 4:15 PM Session Young Professionals |
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A first-order transfer function for temperature control of
flame-sprayed coating-based heating systems
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Jacob John* / University of Alberta, Canada Hossein Rouhani / University of Alberta, Canada André McDonald/ University of Alberta, Canada |
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Flame spraying was used to construct a multi-layered functional coating that acts as a Joule heating element. In order to characterize the applied voltage to the coating to minimize the deicing time while minimizing the required energy, we aimed to investigate a model for dynamic behavior of coating temperature as a function of the applied voltage. To this end, we derived a first-order transfer function from a lumped capacity model to predict the surface temperature change versus the electrical power as the input. A 2cm thick AISI 1018 steel sample was coated with Nickel-Chromium-Aluminum-Yttrium (NiCrAlY), acting as the heating element, and Alumina, acting as the insulator between the element and the sample. Time constant and zero-frequency gain were experimentally obtained for internal forced convection given 3, 6, and 9 V inputs. Also heat transfer coefficient was calculated from the experimental results and used to verify the model against the experimental data. The zero-frequency gain was measured to be 0.265, 0.307, and 0.307 °C/V 2 , for 3, 6, and 9 V inputs while the model predicted 0.32 °C/V 2 . Time constants were measured to be 354, 418, and 399 s for 3, 6, and 9 V inputs while the model predicted 336 s. It was concluded that the transfer function predictions were sufficiently accurate to design a control system. The obtained transfer function can be applied to the design of optimal control systems and sensor-less predictions of temperature. |