Experimental results for oscillatory water flow in 10-ppi metal foam at low-frequencies

This experimental study presents results and interpretation of oscillatory water flow in open-cell metal foam. The tested foam had 10 pores per inch and a porosity of 88%. At relatively low frequencies, three flow displacements were employed in the experiment. The influence of frequency and displacement on pressure loss and friction factor is discussed. A correlation of friction factor as a function of the kinetic Reynolds number was determined. Porous media parameters, permeability and drag coefficient, were also found for the same foam via steady-state flow experiments in the Darcy and Forchheimer regimes. The friction factor of oscillating flow was found to be higher than that of steady state. The findings of this study are considered important for oscillating heat transfer in metal foam

International equatorial electrojet year : the African sector

International audienceThis paper presents the IEEY project in the African sector. The amount of our interpreted data is presently too short to allow proper scientific conclusions. Nevertheless, fist typical results illustrate our network possibilities. Some preliminary observations are briefly pre- , sented for their interest towards immediate research goals

Heat transfer measurements for non-Darcy flow in 10-ppi metal foam

Metal foam is a class of porous media with very high porosity (around 90%) and a large surface area density. The foam internal structure is web-like of thin ligaments surrounding cells that are open to flow. This structure promotes thermal dispersion because it offers a lot of mixing of a flowing fluid. Break up and inception of the boundary layers are phenomena adding to the convective heat transfer. The thermal conductivity of the solid phase of metal foam is also high. Because of all these attributed, metal foam is an excellent heat exchanger technology. There is a need for more experimental data regarding heat transfer in metal form. In this paper, experimental heat transfer data for water flow in commercial open-cell aluminum foam cylinder heated at the wall by a constant heat flux (14,998 W/m2 and 26,347 W/m2), is presented. The foam had 10 pores per inch (ppi) and a porosity around 87%. The measurements included wall temperature along flow direction as well as average inlet and outlet temperatures of the water. Flow speeds were in the non-Darcy regimes: transitional and Forchheimer flow regimes. The behavior of the wall temperature clearly shows thermal development conditions. The experimental Nusselt number is presented as a function of axial distance in flow direction, and showed what seemed to be periodic thermal development. The experimental data can be used for validation of other analytical solutions. The results can also be used to verify numerical models and metal-foam heat exchangers used in air-conditioning for example

Investigation of low-frequency-oscillating water flow in metal foam with 10 pores per inch

In this study, oscillating water flow in metal foam with open cells is investigated experimentally. The metal foam sample has a porosity of 88% and 10 pores. The water was oscillated in the test section with three frequencies between 0.116 Hz and 0.348 Hz, which are considered low for water oscillation, and three flow displacements ranging between 74.35 mm and 111.53 mm. The combinations of frequencies of displacements were studied for their impacts of dimensional and non-dimensional pressure loss quantities. To this purpose, friction factor was correlated as a function of kinetic Reynolds number. The same metal foam sample was studied by exposing it to steady-state water flow to investigate its permeability and drag coefficient in low-velocity flow regimes. The friction factor distribution for oscillating flow was found to be over that found for steady state. The outcomes of the study are important for studying heat transfer under the same flow conditions