Electro-Thermal Analysis of a Micro Heater for aerosol generation application

M.Saberi1, U.Pelz1, M.Ghanam1, T. Bilger1, A.Jamali1, E. Bäumker1, P. Woias1, F. Goldschmidtböing1
1Institut für Mikrosystemtechnik (IMTEK), Albert-Ludwigs-Universität Freiburg, Freiburg im Breisgau, Germany
Published in 2020

There is an increasing demand for aerosol devices from E-cigarettes to drug delivery devices with precise dosage. [1][2] The aim of this article is to investigate a Poly-Si micro heater in a vapor generator device. In order to calculate the amount of vapor production, temperature distribution, and heat loss calculation of the heater a simulation setup was modeled in COMSOL. The setup consists of a rectangular perforated Poly-Si heater which is placed on a wet fiberglass wick material and powered through gold wire bonds to a PCB. The heater chip is mounted inside the PCB using epoxy glue (Figure 1). The simulation implements coupled electrical current, heat transfer, laminar flow physics and events modules. The electrical current and heat transfer modules are coupled using joule heating Multiphysic. The electrical input power is controlled based on temperature of heater using events interface. There is also Non-isothermal flow Multiphysic which couples heat transfer and laminar flow module to account liquid flow and phase change. All domain is manually meshed using mostly hexahedral and prism elements. The amount of vapor product is about 1 mg after 3 seconds with temperature regulation around 270°C. The heat losses to surrounding air via convection and through wire bonds via conduction are negligible, however most of heat goes to the liquid and epoxy material. The evaporation starts at 0.2 seconds and is almost linearly increasing by time.

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