In this paper a comprehensive review of flow visualization techniques used for the analysis of spray characteristics is presented and an experimental demonstration of different lighting techniques has been made. Still photographs of Sprays from an airblast atomizer and a swirl atomizer are taken under backlighting, slit lighting, incident lighting (front flash) and a new method of capturing scattered light image at 1200 to the incident light is introduced in the present work. Photographs taken by these methods are shown to be useful for deriving useful observations such as jet breakup phenomenon, the internal details and the external appearance of the spray. It is demonstrated that the information obtainable from each technique is different and that a combination of different techniques may be necessary for proper diagnosis. The article also includes a discussion on the jet breakup phenomenon as observed in the photographs and in addition a new concept of shear formation of smaller droplets from the surface of a liquid jet by the co-flowing air stream in an airblast atomizer has been proposed.

Experimental and numerical investigation of multihole gasoline direct injection (GDI) Sprays at high injection pressure and temperature are performed. The primary objective of this study is to analyse the role of gas entrainment and spray plume interactions on the global spray parameters like spray tip penetration, spray angles and atomization. Three-hole 90° spray cone angle and six-hole 60° spray cone angle injectors are used for current work to examine the effect of the geometry of the injector on the spray interactions. The numerical results from Reynolds Average Navier Stokes (RANS) simulations show a reasonable comparison to experiments. The simulations provide further insight to the gas entrainment process highlights the fact that a stagnation plane is formed inside the spray cone which basically governs the semi collapse of spray that in turn affects the spray direction and cone angle.

This article discusses the importance of using different turbulence modulation models in simulation of evaporating Sprays. An in-house CFD code has been modified to take into account the effect of considering turbulence modulation by standard or consistent models. These models may predict an augmentation (consistent model) or a reduction (standard model) in the turbulence kinetic energy of continuous phase. Calculations are done in a Eulerian-Lagrangian framework and the effect of injected droplets on turbulent kinetic energy and its rate of dissipation is included in the equations of the continuous phase. Results are shown to be valid by comparing them to Sandia spray A configuration experimental data. Results show that considering the effect of existing droplets in a turbulent combustion chamber can play a major role in having a more accurate CFD simulation. These models can alter the velocity field drastically when droplets are injected into the chamber with a high velocity. As a result, spray characteristics such as evaporation rate is also altered. It can be concluded that modulation models should be used in the simulation of evaporating Sprays in order to attain more accurate and realistic results.

Olive trees have been traditionally cultivated in dry conditions as it is a crop very well adapted to Mediterranean dry lands. Foliar fertilization is a widespread application method used by olive growers to correct frequent deficient levels of potassium in olive trees under rainfed conditions.Monopotassium Phosphate (MKP) is an economic and easily available fertilizer and a fast source of P and K when it is applied as a foliar spray. The influence of environmental and formulation factors on the efficiency of MKP foliar application has never been evaluated. In this study the different responses of five MKP foliar treatments (control-untreated, MKP3% at dayligh, MKP3% overnight, MKP3% plus urea and MKP3% plus surfactant) on olive trees under field conditions were evaluated during three different application times (April, July, and November). In all cases, MKP3% plus urea and MKP3% plus surfactant increased P contents with July being the most effective treatment month.All treatments, except MKP3% at dayligh, improved the K nutritional state of olive in July, but not in November or April. In general, the addition of urea and surfactant to the MKP3% solution and its application in July improved its efficiency on olive trees, most likely due to the higher proportion of young leaves present during this period.