Non-equilibrium heat transfer in metal-foam solar collector with no-slip boundary condition

Xu, Huijin; Gong, Liang; Huang, Shanbo; Xu, Minghai

doi:10.1016/j.ijheatmasstransfer.2014.04.034

Cited by 48 publications

(8 citation statements)

References 29 publications

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“…For Darcy regime, Nu is seen to be generally constant (independent of distance along the foam), albeit with some little scatter, for the three Darcy velocities, which is a confirmation of thermal full-development condition. As expected, Nu is independent of Re for the Darcy cases, which is consistent with what was presented in Hetsroni et al (2005), Xu et al (2014).…”

Section: Local Nusselt Numbersupporting

confidence: 91%

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Forced-Convection Measurements in the Fully Developed and Exit Regions of Open-Cell Metal Foam

2015

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Experimental heat transfer data for water flow in commercial, open-cellaluminum-foam cylinder heated at the wall by a constant heat flux, are presented. The measurements include wall temperature along flow direction as well as average inlet and outlet temperatures of the water. Flow speeds were in the Darcy and non-Darcy (transitional and Forchheimer) regimes. Heat fluxes were 14,998 and 26,347 W/m 2 for the Darcy and nonDarcy regimes, respectively. Measurements were focused on the thermally fully developed and an anticipated exit regions, with the latter region being often ignored in the literature. The experimental Nusselt number for the Darcy flow cases is compared to its analytical counterpart. A comparison shows good agreement, considering the approximations involved in the analytical solution and experimental errors. Previously unpublished phenomenon is presented in the behavior of Nusselt number for non-Darcy regimes. The experimental results and measuring technique can be used for validation of other analytical and numerical solutions, as well as in testing heat-exchange engineering designs based on metal foam. List of symbolsU Mean flow velocity (m s −1 ) r o Radius of foam cylinder (m) z Axial coordinate along flow direction (m) Greek μ Viscosity (Pa s) ρ Density (kg m −3 )

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Section: Local Nusselt Numbersupporting

confidence: 91%

“…The solid straight lines for each case have curve-fit factor R 2 > 0.99. The constant slope of the wall temperature is indeed a sign of full thermal development (Qu et al 2012;Xu et al 2014):…”

Section: Wall Temperature Thermal Fully Developed and Exit Regionsmentioning

confidence: 99%

Forced-Convection Measurements in the Fully Developed and Exit Regions of Open-Cell Metal Foam

2015

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“…Metal foams, a type of porous media, have been applied in experimental and analytical studies as heat transfer enhancement modifications. In particular, for solar collector applications, Wang, Shuai, Tan, and Yu (2013) and Xu, Gong, Huang, and Xu (2014) found metal foams to have greatly enhanced the thermal performance of solar collectors, based on their analysis. In several analyses of solar collectors with metal foams, the Darcy, Brinkman, and Forchheimer models were employed to model flow through a porous media.…”

Section: Porous Mediamentioning

confidence: 99%

“…The Darcy equation is the governing equation of the flow through a porous media, the Brinkman model is formed by including viscous dissipation effect to the Darcy model (used when the flow is slow or if the fluid has a low viscosity) and the Forccheimer model is the Darcy equation with an inertial term (used for high velocity flows). Xu et al (2014) analytically and numerically examined the effect of porosity, pore density (measured in pores per in, PPI), channel height, and Reynolds number on the thermal performance of a solar collector; the air channel enveloped block of metal foam. With respect to the velocity profile, they found that applying the Forccheimer resulted in a more uniform profile, than the Darcy or Brinkman model; this is due to the inertial term which would also result in a greater pressure drop Xu et al (2014).…”

Section: Porous Mediamentioning

confidence: 99%

“…Xu et al (2014) analytically and numerically examined the effect of porosity, pore density (measured in pores per in, PPI), channel height, and Reynolds number on the thermal performance of a solar collector; the air channel enveloped block of metal foam. With respect to the velocity profile, they found that applying the Forccheimer resulted in a more uniform profile, than the Darcy or Brinkman model; this is due to the inertial term which would also result in a greater pressure drop Xu et al (2014). This loss can be prevented by increasing the permeability (e.g., lowering foam density) (Xu et al, 2014).…”

Section: Porous Mediamentioning

confidence: 99%

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Thermal enhancement of a building integrated photovoltaic/thermal system coupled with an air source heat pump

Vuong¹

2021

Preprint

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Enhancements of a building integrated photovoltaic/thermal (BIPV/T) system intended for coupling with an air source multispeed heat pump (MSHP) is presented. The systems were analyzed using a modified version of EnergyPlus, a quasi-steady state building energy simulation program. A sensitivity analysis of the internal channel surface and cover emissivity parameters of the Opaque BIPV/T, transparent BIPV/T, and building integrated solar air heater collectors (BISAH) was conducted. In addition, collector arrangement analyses were performed. A BIPV/T- BISAH array design was selected based on the results of the analyses and evaluated using a net-zero energy house and an energy efficient house. The integrated BIPV/T-BISAH coupled ASHP system reduced space heating electricity consumption of the net-zero house by 6.5% and the energy efficient house by 3.4%. These low levels of savings were largely due to the passive design of the houses that reduced heating loads during sunny hours; this resulted in a mismatch between the hours when the integrated system could provide energy savings and the need for space heating.

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MHD forced convection of nanofluid flow in an open-cell metal foam heatsink under LTNE conditions

Izadi

Abdipour

Rasam

2020

J Therm Anal Calorim

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Non-equilibrium heat transfer in metal-foam solar collector with no-slip boundary condition

Cited by 48 publications

References 29 publications

Forced-Convection Measurements in the Fully Developed and Exit Regions of Open-Cell Metal Foam

Forced-Convection Measurements in the Fully Developed and Exit Regions of Open-Cell Metal Foam

Thermal enhancement of a building integrated photovoltaic/thermal system coupled with an air source heat pump

MHD forced convection of nanofluid flow in an open-cell metal foam heatsink under LTNE conditions

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