Master of Sciences, Case Western Reserve University, 2019, EMC - Mechanical Engineering

Solar panels installed on residential rooftops have gained popularity because of their economic efficiency as well as environmental friendliness. However, this type of installation affects the fire performance on the rooftop and introduces new fire concerns. To gain a fundamental understanding of this process, a gas burner fire over an inclined surface (90 cm wide and 440 cm long) with and without a parallel top panel is numerically simulated using FireFOAM. Cases with three different inter-panel distances (6.25 cm, 12.5 cm, and 25 cm) and a case without the top panel are simulated. The results show that the top panel has multiple effects on the fire behaviors. First, it reflects and increases the radiative heat input on the bottom panel. Second, it confines the flow between the two panels and forces the flame to stay close to the bottom panel, increasing the conductive heat flux onto the bottom panel. Third, the top panel reduces the fresh air (oxygen) that enters the fire domain. When the equivalence ratio drops below one, this effect impedes the gas-phase reaction and decreases the gas-phase temperature, and hence the heat flux on the lower panel. As a result of these effects, the flame temperature and heat flux on the lower panel first increases and then decreases when the inter-panel distance decreases. Physics-based mitigation strategies are proposed and shown effective to alleviate the adverse effects of the solar panels on the rooftop fire performance.

Committee: Ya-ting Liao (Committee Chair); James T'ien (Committee Member); Fumiaki Takahashi (Committee Member) Subjects: Mechanical Engineering