Chetankumar Patel

Introduction to Droplets and Sprays: Applications for Combustion and Propulsion

Spray characteristics play an important role in determining efficiency of gas turbine, rocket combustors and internal combustion engines. Droplet atomization and break-up forms the fundamental building block in many spray-based applications. Detailed analysis of the internal and the near-nozzle flow of fuel injectors is a necessity for a comprehensive understanding of any internal combustion engine performance. Understanding turbulence is one of the most difficult topics in science and engineering. In liquid fuelled combustion, the interaction of spray droplets with surrounding turbulent air flow is crucial since it influences the evaporation rate of the fuel droplets and the process of air and fuel vapour mixture preparation. For detail understanding on the droplet–turbulence interaction mechanisms as well as to validate numerical simulations of sprays, simultaneous measurement of both dispersed and carrier phases of the spray is essential. Turbulent spray combustion involves many areas of physics and chemistry, which accompany a variety of mathematical challenges. This monograph deals with all above aspects to enhance the understanding of spray characteristics involved with different applications.

Introduction to Application Paradigms of Droplets and Spray Transport

Droplets and sprays are ubiquitous in variety of multiphase, multiscale applications spanning across surface patterning, oil recovery, combustion, atomization, spray drying, thermal barrier coating, renewable energy, electronic cooling, to name a few. This book provides two levels of detailing pertaining to such applications. Each chapter of this book delves into the intricacies of one such application and provides not only an overview but also details of the physical insights into the application mechanisms from the point of view of droplets and sprays. In this book, the authors aimed to provide not just a brief overview but also to answer questions like what is the behavior of droplets, what are the measurement techniques available to study and control such these phenomenon, and how the droplet transport can be measured and monitored using modern optical diagnostics.

Biodiesel Soot Characteristics

Diesel engines are widely utilized as a power source in various applications, such as passenger and commercial vehicles, electricity generation, marine transportation, and construction equipment. Despite several advantages for instance, low operating cost, high durability, and high power-to-weight ratio, diesel engines have the inherent disadvantage of high NOx and soot emissions. In terms of environmental concerns, oxygenated fuels such as biodiesel have been considered as a promising alternative fuel for diesel engines. It is well known that the oxygen content of biodiesel suppresses the formation of soot precursors in diffusion flames. Many researchers are now trying to examine the soot formation with biodiesels. In this chapter, the effect of biodiesel on soot particles in compression ignition engines is discussed. The morphological characteristics of soot particles were analyzed with transmission electron microscope (TEM). The chemical composition was determined by the elemental analysis (EA) and thermogravimetric analysis (TGA). From the previous studies, it emerged that soot particles from biodiesel were composed of smaller primary particles compared to those in case of diesel. The nano-structure analysis of biodiesel soot particles showed that biodiesel origin soot is preferable for oxidation due to its unstable graphene structure. On the other hand, biodiesel soot particles were composed of lesser carbonaceous materials. They contained lower carbon-containing species but higher hydrogen, oxygen, and nitrogen in the soot.