Thermal behavior of open cell aluminum foams in forced air: Experimental analysis Stefano Guarino a,⇑ , Gianluca Rubino b , Vincenzo Tagliaferri c , Nadia Ucciardello c a University ‘Niccolò Cusano’, Department of Engineering, Via Don Carlo Gnocchi 3, 00166 Rome, Italy b University ‘La Tuscia’, Department of Economy, Via S.M. in Gradi, n.4, 01100 Viterbo, Italy c University of Rome ‘Tor Vergata’, Department of Enterprise Engineering, Via del Politecnico 1, 00133 Rome, Italy article info Article history: Received 5 December 2013 Received in revised form 27 February 2014 Accepted 23 September 2014 Available online 15 October 2014 Keywords: Aluminum foam Open cell Convective heat transfer Pressure drops abstract This paper deals with the study of thermal and fluid dynamics properties of the open cell metal foams. A thermo-fluid dynamic analysis of three different types of aluminum alloy foams, 5, 10 and 20 pores per inch (PPI) was carried out by using a novel ad hoc built instrumentation. In particular, it has been investigated the Heat Transfer Coefficient (HTC * ) and the Pressure Drop (PD) under a flow of forced humid air. The influence of the main parameters, temperature of the metal foam and speed of humid air, both on the HTC * and on the PD was examined. Design of experiments (DOE) approach was used as support to interpret the experimental findings and the physical phenomena involved in HTC * and in PD, between foams and air. The analysis permitted to detect the effects of the operational parameters, foam pore size, air flux and temperature on the HTC * and on the PD. Ó 2014 Elsevier Ltd. All rights reserved. 1. Introduction Aluminum foams are a recent class of cellular materials with very interesting mechanical and thermal characteris- tics. These new materials have been stimulating great interest in many technological domains. As structural materials, aluminum foams have been cre- ating high interest due to their lightweight structure and good physical, chemical and mechanical properties like high specific stiffness and good energy absorbing. These properties make them suitable for many industrial applica- tions in fields like automotive, aerospace, packaging, etc. [1,2]. Moreover, metal foams with open cell structure have attractive heat-transfer properties, hence allowing its employment in cooling equipment and as heat exchangers [3–5]. Different foaming processes have been developed and reported in literatures [1,6,7] and [8]. Each method can be chosen with selected metals, depending on the mor- phology (closed cell or open cell structure), density and cell size desired. The final properties and the morphology of the foam produced make it suitable for specific applica- tions in different industrial domains [9,10]. Open cells metal foams present structures randomly oriented and mostly homogeneous in size and shape. Most commercially available metal foams are produced in alumi- num, copper, nickel and metal alloys. Metal foams have interesting applications in heat exchangers, cryogenics, combustion chambers, cladding on buildings, strain isola- tion, geothermal operations, petroleum reservoirs, catalytic beds, compact heat exchangers for airborne equipment, air-cooled condensers for air conditioning and refrigeration systems, and compact heat sinks for power electronics [9,10]. http://dx.doi.org/10.1016/j.measurement.2014.09.069 0263-2241/Ó 2014 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. E-mail addresses: stefano.guarino@uniroma2.it (S. Guarino), gianluca. rubino@unitus.it (G. Rubino), tagliafe@uniroma2.it (V. Tagliaferri), nadia. ucciardello@uniroma2.it (N. Ucciardello). Measurement 60 (2015) 97–103 Contents lists available at ScienceDirect Measurement journal homepage: www.elsevier.com/locate/measurement