Preface

Within a few hundred years of the Industrial Revolution, humans discovered or fabricated thousands of foam fluids and materials that have been utilized in petroleum extraction, chemical engineering, the textile and architecture industries, and more. In addition to synthesized foams, there are considerable foams found in nature that are very stable evolutionary and bionic structures. Foam structures have been widely studied and applied in many subjects, and scholars in the field have played an indelible role in developing foam-related theories that are being used to figure out how to make better use of foams today.

Foams are ubiquitous in human life. For example, foams are found in sodas and sponges in liquid form and solid form, respectively. Various foams have distinctive properties that can be used to develop special usages in engineering applications. This book reviews, researches, and summarizes the knowledge and experience of foam fluids and porous foams in industry. Compared with simpler fluids, foam fluids are more complicated to describe by conventional rules because of their phase discontinuity. Considering that foam fluids can be applied to displace oil or gases underground, research on foam fluids is of great significance. Porous foams consist of solid metal and fluid-filled pores that take up a certain portion of the entire volume. This structural feature makes porous foams mechanically stable with lighter mass. In addition, porous foams have terrific performance when employed in energy absorption and heat exchange. Nevertheless, the pores existing in porous foams add the difficulties of modeling and calculating the fluid flow. Fortunately, this book addresses this issue and provides possible solutions.

Chapter 1 reviews recent developments in the manufacture and characterization of multiphase foams developed by incorporating new phases into open-pore foam materials. The new incorporated phases can significantly alter the macro-/ microstructure of the starting materials or modify the pore surfaces to achieve new functionalities, which exhibits a great potential for use in electronics, medicine, or catalysis.

Chapter 2 discusses state-of-the-art acoustic and thermal models and their application to cellular foam materials. Five different forecasting methods including traditional analytical, a modified analytical with a new proposed equation, and inverse procedures were employed to determine the Johnson–Champoux–Allard (JCA) parameters related to the sound-absorbing properties of foam materials. Numerical results indicate that the inverse procedure, using the thermal characteristic length derived from the scanning electron microscope (SEM) micrographs as the imposed parameter, well agrees with the modified analytical model.

Chapter 3 presents a turbulent heat transfer analysis of silicon carbide ceramic foam as a solar volumetric receiver. Both the Rosseland approximation and the P1 model are applied to consider the radiative heat transfer through the solar receiver. In light of the derived analytical solutions, it is found that the corresponding fluid and solid temperature variations generated under the Rosseland approximation agree fairly well with those based on the P1 model. Furthermore, optimal pore diameter that exists for achieving the maximum receiver efficiency under the equal pumping power is obtained, which provides effective guidance for a novel volumetric solar receiver design of silicon carbide ceramic foam.

Chapter 4 shows how to obtain sintered self-glazed glass-ceramics and/or glass ceramic foams with improved properties and differences in structure by means of a double-stage heat treatment. The sintering of the samples is studied by optical dilatometry and the foaming process by hot-stage microscopy, while the structure of the final materials is revealed by 3D computed tomography and SEM. The phase composition of the glass-ceramic foams is analyzed by XRD. Due to excellent material characteristics, the synthesized inorganic glassy-crystalline foam materials can be used as low-cost thermal insulating, soundproofing, and fire-resisting low-weight materials.

Chapter 5 uses casting techniques to design a new foam product and develop a new method of production to overcome shortcomings. The knowledge gained from this work is valuable for planning future actions for further improving aluminum metallic foam.

Chapter 6 proposes a novel approach to increase stability by introducing nano-sized additives SiO2 and Fe(OH)3 sols to improve the quality of construction foam on a protein basis for non-autoclaved foam concrete. Various stabilization mechanisms related to different energies of chemical bonds formed between the molecules of the foaming agent and the injected sols have been found. The stabilization of the construction foam leads to the possibility of using foam concrete hardening accelerators without destroying its structure, which is beneficial to obtain increased compressive and bending tensile strength and reduce thermal conductivity and shrinkage in drying.

Chapter 7 highlights the different CO2-foam generation mechanisms and the deterioration effect of crude oil on CO2-foam stability, so as to improve sweep efficiency in enhanced oil recovery (EOR) applications over that of polymers. Several nanoparticles such as aluminum oxide, copper oxide, and silicon dioxide are considered. The results indicate that silicone dioxide with a modified surface is more effective in foam stability applications.

In each of these chapters, we spared no efforts to provide sufficient and logical information for readers, and tried our best to establish the foundation of relevant research topics. Experts in the field reviewed each chapter of this book. As the author of this book, I am looking forward to receiving feedback and constructive comments from readers and experts.
