Numerous engineering applications involve dropwise cooling of hot solid surfaces, which has become a major research task for both academia and industry. This work focuses on single-phase evaporation regime, proposing a fully non-intrusive technique to measure the solid/liquid interface temperature and a simple numerical code to evaluate heat flux. A comparison between a single droplet and two sequentially released droplets is presented. Infrared thermography was used to measure the transient contact temperature of droplets released onto a BaF2 disk coated by a black-painted layer; interface temperature was measured from below through the solid body. The total released volume of water was kept constant; droplet Weber number was lower than 70; the initial surface temperature was nominally 80 °C. A self-developed numerical code was developed to simulate the evaporation mechanism under single-phase evaporation regime. The three-dimensional energy diffusion equation describing the transient within both the liquid and the solid phase was discretized by the finite-volume method. The model aims at ultimately predicting the heat-flux distribution at the solid/liquid interface. Flux distribution was obtained for both the single- and the two-droplet case; moreover, heat flux was evaluated all over the sampling region. Validation was performed as a comparison between numerical and experimental temperature datasets at the substrate surface, showing very good agreement for both the cases, especially for the wetted regions. The single-droplet configuration is shown to provide overall higher cooling effect, whereas the multi-droplet has longer and more effective cooling on the area of mutual interaction between droplets.

Spray cooling by gently-deposited droplets: Experiments and modeling of heat-transfer mechanisms / Santangelo, Paolo Emilio; Corticelli, Mauro Alessandro; Tartarini, Paolo. - (2014). ((Intervento presentato al convegno 15th International Heat Transfer Conference (IHTC15) tenutosi a Kyoto, Giappone nel 10-15 agosto 2014 [10.1615/IHTC15.evp.008367].

Spray cooling by gently-deposited droplets: Experiments and modeling of heat-transfer mechanisms

Paolo Emilio Santangelo;Mauro Alessandro Corticelli;Paolo Tartarini
2014

Abstract

Numerous engineering applications involve dropwise cooling of hot solid surfaces, which has become a major research task for both academia and industry. This work focuses on single-phase evaporation regime, proposing a fully non-intrusive technique to measure the solid/liquid interface temperature and a simple numerical code to evaluate heat flux. A comparison between a single droplet and two sequentially released droplets is presented. Infrared thermography was used to measure the transient contact temperature of droplets released onto a BaF2 disk coated by a black-painted layer; interface temperature was measured from below through the solid body. The total released volume of water was kept constant; droplet Weber number was lower than 70; the initial surface temperature was nominally 80 °C. A self-developed numerical code was developed to simulate the evaporation mechanism under single-phase evaporation regime. The three-dimensional energy diffusion equation describing the transient within both the liquid and the solid phase was discretized by the finite-volume method. The model aims at ultimately predicting the heat-flux distribution at the solid/liquid interface. Flux distribution was obtained for both the single- and the two-droplet case; moreover, heat flux was evaluated all over the sampling region. Validation was performed as a comparison between numerical and experimental temperature datasets at the substrate surface, showing very good agreement for both the cases, especially for the wetted regions. The single-droplet configuration is shown to provide overall higher cooling effect, whereas the multi-droplet has longer and more effective cooling on the area of mutual interaction between droplets.
15th International Heat Transfer Conference (IHTC15)
Kyoto, Giappone
10-15 agosto 2014
Santangelo, Paolo Emilio; Corticelli, Mauro Alessandro; Tartarini, Paolo
Spray cooling by gently-deposited droplets: Experiments and modeling of heat-transfer mechanisms / Santangelo, Paolo Emilio; Corticelli, Mauro Alessandro; Tartarini, Paolo. - (2014). ((Intervento presentato al convegno 15th International Heat Transfer Conference (IHTC15) tenutosi a Kyoto, Giappone nel 10-15 agosto 2014 [10.1615/IHTC15.evp.008367].
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11380/1108429
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