The process of agricultural production in Brazil has as a main gear the application of chemicals carried out by spraying machines. This study aimed to identify possible interactions between the tips of spraying nozzles, application time and fungicides on the control of Asian soybean rust (Phakopsora pachyrhizi Sidow) in three different cultivars. The work was carried out in Itaara - RS, spray nozzles used were XR 11002 (jet plan expanded use), TX 8002 (empty cone), TT 11002 (turbo fan), TJ60 11002 (twin flat) and AI 11002 (fan anti-drift). Applications were made at 8:00, 10:00 and 12 hours with fungicides cyproconazole+picoxystrobin and epoxiconazole+pyraclostrobin in R1 growth stage and repeated the second application 21 days after first in cultivars M-SOY 8000 RR, AL 72 and Agiara. Analysis of variance revealed a significant interaction between cultivars, spray nozzles and the application time for all variables, showing that several factors affect application technology. The increase of grain yield promoted by fungicides, in the average of application times ranged between nozzles, according to the cultivar. The cultivar AL 72 results showed the smallest variation between nozzles. The increase in grain yield promoted by treatments with different nozzles ranged between 37.39 and 45.75% for the fungicide pyraclostrobin + epoxiconazole and 32.38 and 39.34% for the fungicide ciproconzaol + picoxystrobin / O processo de produção agrícola no Brasil tem como uma das engrenagens principal como a aplicação de produtos químicos realizados por máquinas de pulverização. O presente trabalho visou identificar possíveis interações entre pontas de pulverizações, horário de aplicação, cultivares de soja e fungicidas no controle da ferrugem asiática da soja (Phakopsora pachyrhizi Sidow). O trabalho foi realizado em Itaara RS, as pontas de aplicação utilizadas foram XR 11002 (jato plano de uso ampliado), TX 8002 (jato cônico vazio), TT 11002 (jato plano de ângulo grande), TJ60 11002 (jato plano duplo comum) e AI 11002 (jato plano com indução de ar). Foram realizadas aplicações as 8h00min, 10h00min e 12h00min com os fungicidas ciproconazol + picoxistrobina e epoxiconazol + piraclostrobina no estádio fonológico R1 e repetido a segunda aplicação 21 dias após, nas cultivares M-SOY 8000 RR, AL 72 e Agiara. A análise de variância revelou interação significativa entre cultivares, pontas de pulverização e horários de aplicação para todas as variáveis analisadas, demonstrando que diversos fatores afetam a tecnologia de aplicação. O incremento no rendimento de grãos promovido pelos fungicidas, na média dos horários de aplicação, apresentou variação entre pontas de pulverização, conforme a cultivar utilizada. A cultivar AL 72 foi aquela que apresentou a menor variação entre as pontas de pulverização. O incremento no rendimento de grãos promovido pelos tratamentos com as diferentes pontas de pulverização variou entre 37,39 e 45,75% para o fungicida epoxiconazol + piraclostrobina e 32,38 e 39,34% para o fungicida ciproconzaol + picoxistrobina

Pesticide drift is a serious agricultural problem that is especially significant for perennial crops. Most studies use tracers to quantify pesticide drift. Nevertheless, in Brazil, consensus is lacking on which tracer is the most effective. Thus, given the importance of coffee crops in Brazil, we evaluated several tracers used in application efficiency assessments. We also quantified the drift in coffee crops from hollow cone nozzles with and without air induction and then compared the results with European drift simulation models. We tested Brilliant Blue, Blankophor, Sodium Fluorescein, Rhodamine B and Brilliant Sulfoflavine tracers by evaluating surface tension, hidrogenionic potential, filter paper extraction, sunlight stability and agitation stability. Drift evaluation was based on the ISO 22866 standard. The experiment was set up in randomized blocks with 10 replications in a 2 x 20 split plot consisting of two nozzle types and twenty lines spaced 2.5 m apart and parallel to the target crop row. The spray was a mixture of water and Rhodamine B fluorescent dye at 100 mg L-1. The spray was applied at 400 L ha-1 using a hydro-pneumatic sprayer. Viscosity was similar for all tracers. Brilliant Sulfoflavine had the highest extraction efficiency, whereas Brilliant Sulfoflavine and Brilliant Blue were the most stable in sunlight. Blankophor had the least agitation stability and Brilliant Sulfoflavine was the most appropriate for spray deposition and drift assessment. Rhodamine B was the best option for filter paper targets among low-cost tracers available in Brazil. The air induction nozzle reduced drift to 20 m from the treated area; however, both nozzles produced the same drift within this limit. The drift models behaved differently and did not accurately estimate drift near the target row. / A deriva de produtos fitossanitários é um dos maiores problemas da agricultura moderna, principalmente em cultivos perenes. Ao quantificar esta e outras perdas dos produtos, na maioria dos casos são utilizados traçadores. Devido à importância da cafeicultura no Brasil, e que não há consenso sobre qual é o melhor traçador nestes estudos, este trabalho objetivou avaliar alguns traçadores utilizados em estudos de eficiência da aplicação, além de determinar a deriva gerada pelas pontas de pulverização jato cônico vazio com e sem indução de ar nas aplicações na cultura do café e comparar as curvas com modelos europeus de simulação de deriva. Os traçadores utilizados foram: Azul Brilhante, Blankophor, Fluoresceína Sódica, Rodamina B e Sulfoflavina Brilhante. As características avaliadas nas soluções contendo os traçadores foram: tensão superficial, pH, viscosidade, extração em alvos de papel filtrante e estabilidade à luz solar e à agitação. Na avaliação da deriva ocasionada pelas aplicações em cafeeiro, seguiu-se a norma ISO 22866. Foi utilizado o delineamento em blocos casualizados, com 10 repetições, em esquema de parcelas subdivididas no espaço 2 x 20, sendo dois tipos de pontas e vinte distâncias paralelas à linha de cultivo fora da área-alvo, espaçadas entre si por 2,5 m. A calda foi composta por água+corante fluorescente rodamina B na concentração de 100 mg L-1. Utilizou-se o volume de calda de 400 L ha- 1, aplicado por pulverizador hidropneumático. Dentre as características físico-químicas, somente a viscosidade não foi influenciada pelos traçadores. A maior eficiência de extração em alvo de papel foi obtida pela Sulfoflavina Brilhante, que juntamente com o Azul Brilhante demonstraram ser os traçadores mais estáveis à luz solar. O Blankophor foi o traçador que teve menor estabilidade à agitação da calda. A Sulfoflavina Brilhante mostrou ser o traçador mais adequado aos estudos de deposição de calda e deriva nas aplicações de produtos fitossanitários. Entre os traçadores de baixo custo e maior disponibilidade no Brasil, o corante fluorescente Rodamina B apresentou ser a melhor opção ao se utilizar como alvo papel filtrante. A ponta de jato cônico vazio com indução de ar reduziu a deriva até 20 m de distância da área tratada. A partir dessa distância, ambas as pontas geraram a mesma deriva. As curvas de deriva elaboradas a partir das aplicações pelas pontas de pulverização demonstraram ter comportamentos diferentes, sobretudo na região mais próxima do cafeeiro. / Mestre em Agronomia

[pt] A utilização de escoamentos bifásicos borbulhantes com dois componentes é muito utilizada em equipamentos industriais, particularmente quando existe um grande interesse em promover uma mistura eficiente entre os componentes. um dos equipamentos capazes de promover estas condições é o bocal convergente-divergente. O objetivo deste trabalho é simular o escoamento de misturas bifásicas borbulhantes neste tipo de bocal. Dados experimentais com uma mistura de ar e água foram levantados a partir da construção de um bocal em resina, avaliando-se as pressões nas seções convergente, garganta e divergente. A análise destes dados e a comparação com teorias existentes (N. T. Thang e D. Chisholm) permitiu a definição de um modelo, similar ao método do coeficiente C desenvolvido por Chisholm, adotando-se coeficientes experimentais distintos para as seções convergente, garganta e divergente. Foram determinadas as incertezas experimentais e do modelo, o que permitiu a comparação entre as teorias. Para a primeira (N. T. Thang) foi determinada experimentalmente a relação entre as velocidades do gás e do líquido como função da relação entre a vazão mássica do gás e a vazão volumétrica do líquido. De um modo geral, as teorias prospostas por N. T. Thang e D. Chisholm só se aproximaram dos dados experimentais na seção convergente. Na seção divergente e na garganta, sugere-se a utilização do modelo proposto com coeficiente C experimental. / [en] Two phase bubblyflow of two components has widespread applications in industries when efficient mixture in equipaments is required. High rates of mixing are frequently obtained in a converging-diverging nozzle flow. In this investigation a resin made converging-diverging nozzle was designed and built, with pressure taps drilled along its axis, so that the water-air mixture properties could be investigated under the bubbly flow regime. The experimental data was compared to the predicted values by two existing theories(N. T. Thang and D. Chisholm), using the estimated uncertainty of results, showing that in the converging section of the nozzle, the predicted pressure profile matches with the experimentally one. In order to usa Thang s theory, the gas-liquid velocity ratio was experimentally determined as a function of their mass flow rate ratio. A prediction scheme for the throat and the divergent section of the nozzle, using a modification of Chisholm s C coeficient method, was developed using the experimental data of this investigation. It is proposed in this work a prediction scheme for the whole nozzle flow, under the bubbly flow regime.

Many industrial applications acquire necessary thermal energy through the combustion process. The basic element of each combustion appliance is a burner and one~part~of~it~is a~nozzle system that supplies fuel to a combustion chamber. The geometry of the fuel nozzle significantly affects the intensity of mixing the fuel with the combustion air and thus the stability of the combustion. The main subject of~this diploma thesis is~determination of~velocity coefficients for nozzles with different geometries. The knowledge of~correct values of~velocity coefficients is a key parameter for the design of~the burner and~its subsequent operation. For the calculation of~velocity coefficients, the exit nozzle velocities were used. For chosen nozzles, a~theoretical exit nozzle velocities were calculated. They were compared with the actual exit nozzle velocities, which were measured experimentally using the hot-wire anemometry, and with velocities, which were calculated using the CFD simulation method.

The diploma thesis named Heat exchanger with a combined condensation deals with design of the heat exchanger with a combined condensation. The first part is a brief research about direct-contact heat exchangers. The next part describes physical principles of direct-contact heat transfer mechanisms and a method of calculation is proposed. After that the bundle with basic dimension of heat exchanger is designed. The mixing chamber is designed based on these dimension. Technical documentation of a heat exchanger with combined condensation is an integral part of the thesis.

No description available.

Convergent-Divergent (C-D) nozzles are used in rocket engines to produce thrust as a reaction to the acceleration of hot combustion chamber gases in the opposite direction. To maximize the engine performance at high altitudes, large area ratio, bell-shaped or contoured nozzles are used. At lower altitudes, the exit pressure of these nozzles is lower than the ambient pressure. During this over-expanded condition, the nozzle-internal flow adapts to the ambient pressure through an oblique shock. But the boundary layer inside the divergent portion of the nozzle is unable to withstand the pressure rise associated with the shock, and consequently flow separation is induced. Numerical simulation of separated flows in rocket nozzles is challenging because the existing turbulence models are unable to correctly predict shock-induced flow separation. The present thesis addresses this problem. Axisymmetric, steady-state, Reynolds-Averaged Navier-Stokes (RANS) simulations of a conical nozzle and three sub-scale contoured nozzles were carried out to numerically predict flow separation in over-expanded rocket nozzles at different nozzle pressure ratios (NPR). The conical nozzle is the JPL 45◦-15◦ and the contoured nozzles are the VAC-S1, the DLR-PAR and the VAC-S6-short. The commercial CFD code ANSYS FLUENT 13 was first validated for simulation of separated cold gas flows in the VAC-S1 nozzle. Some modeling issues in the numerical simulations of flow separation in rocket nozzles were determined. It is recognized that compressibility correction, nozzle-lip thickness and upstream-extension of the external domain are the sources of uncertainty, besides turbulence modeling. In high-speed turbulent flows, compressibility is known to affect dissipation rate of turbulence kinetic energy. As a consequence, a reduction in the spreading rate of supersonic mixing layers occurs. Whereas, the standard turbulence models are developed and calibrated for incompressible flows and hence, do not account for this effect. ANSYS FLUENT uses the compressibility correction proposed by Wilcox [1] which modifies the turbulence dissipation terms based on turbulent Mach number. This, as shown in this thesis, may not be appropriate to the prediction of flow separation in rocket nozzles. Simulation results of the standard SST model, with and without the compressibility correction, are compared with the experimental data at NPR=22 for the DLR-PAR nozzle. Compressibility correction is found to cause under-prediction of separation location and hence its use in the prediction of flow separation is not recommended. In the literature, computational domains for the simulation of DLR subscale nozzles have thick nozzle-lips whereas for the VAC subscale nozzles they have no nozzle-lip. Effect of nozzle-lip thickness on flow separation is studied in the DLR-PAR nozzle by varying its nozzle-lip thickness. It is found that nozzle-lip thickness significantly influences both separation location and post-separation pressure recovery by means of the recirculation bubbles formed at the nozzle-lip. Usually, experimental values of free stream turbulence are unknown. So conventionally, to minimize solution dependence on the boundary conditions specified for the ambient flow, the computational domain external to the nozzle is extended in the upstream direction. Its effect on flow separation is studied in the DLR-PAR nozzle through simulations conducted with and without this domain extension. No considerable effect on separation location and pressure recovery is found. The two eddy-viscosity based turbulence models, Spalart-Allmaras (SA) model and Shear Stress Transport (SST) model, are well known to predict separation location better than other eddy-viscosity models, but with moderate success. Their performances, in terms of predicting separation location and post-separation wall pressure distribution, were compared with each other and evaluated against experimental data for the conical and two contoured nozzles. It is found that they fail to predict the separation location correctly, exhibiting sensitivity to the range of NPRs and to the type of nozzle. Depending on NPR, the SST model either under-predicts or over-predicts Free Shock Separation (FSS). Moreover, it also fails to capture Restricted Shock Separation (RSS). With compressibility correction, it under-predicts separation at all NPRs to a greater extent. Even though RSS is captured by using compressibility correction, the transition from FSS to RSS is over-predicted [2]. Early efforts by few researchers to improve predictions of nozzle flow separation by realizability corrections to turbulence models have not been successful, especially in terms of capturing both the separation types. Therefore, causes of turbulence modeling failure in predicting nozzle flow separation correctly were further investigated. It is learnt that limiting of the shear stress inside boundary layer, due to Bradshaw’s assumption, and over-prediction of jet spreading rate are the causes of SST model’s failure in predicting nozzle flow separation correctly. Based on this physical reasoning, values of the a 1 parameter and the two diffusion coefficients σk,2 and σω,2 were empirically modified to match the predicted wall pressure distributions with experimental data of the DLR-PAR and the VAC-S6-short nozzles. The results confirm that accurate prediction of flow separation in rocket nozzles indeed depends on the correct prediction of spreading rate of the supersonic separation-jet. It is demonstrated that accurate RANS simulation of flow separation in rocket nozzles over a wide range of NPRs is feasible by modified values of the diffusion coefficients in turbulence model.

Thesis submitted in fulfilment of the requirements for the degree Master of Technology: Civil Engineering in the Faculty of Engineering at the CAPE PENINSULA UNIVERSITY OF TECHNOLOGY 2014 / The current problems of orifice, nozzle and Venturi flow meters are that they are limited to turbulent flow and the permanent pressure drop produced in the pipeline. To improve these inadequacies, converging-diverging (C-D) tubes were manufactured, consisting of symmetrical converging and diverging cones, where the throat is the annular section between the two cones, with various angles and diameter ratios to improve the permanent pressure loss and flow measurement range. The objective of this study was firstly to evaluate the permanent pressure loss, secondly to determine the discharge coefficient values for various C-D tubes and compare them with the existing differential pressure flow meter using Newtonian and non-Newtonian fluids, and finally to assess the performance of these differential pressure flow meters. The tests were conducted on the multipurpose test rig in the slurry laboratory at the Cape Peninsula University of Technology. Newtonian and non-Newtonian fluids were used to conduct experiments in five different C-D tube flow meters with diameter ratios (β) of 0.5, 0.6 and 0.7, and with angles of the wall to the axis of the tube (θ) of 15°, 30° and 45°. The results for each test are presented firstly in the form of static pressure at different flow rates. It was observed that the permanent pressure loss decreases with the flow rate and the length of the C-D tube. Secondly, the results are presented in terms of discharge coefficient versus Reynolds number. It was found that the Cd values at 15° drop earlier than at 30° and 45°; when viscous forces become predominant, the Cd increases with increasing beta ratio. The Cd was found to be independent of the Reynolds number for Re>2000 and also a function of angle and beta ratio. Preamble Performance of a symmetrical converging-diverging tube differential pressure flow meter Finally, the error analyses of discharge coefficients were assessed to determine the performance criteria. The standard variation was found to increase when the Reynolds number decreases. The average discharge coefficient values and their uncertainties were determined to select the most promising C-D tube geometry. An average Cd of 0.96, with an uncertainty of ±0.5 % for a range of Reynolds numbers greater than 2,000 was found. The comparison between C-D tubes 0.6(15-15) and classical Venturi flow meters reveals that C-D 0.6(15-15) performs well in turbulent range and shows only a slight inaccuracy in laminar. This thesis provides a simple geometrical differential pressure flow meter with a constant Cd value over a Reynolds number range of 2000 to 150 000.

The present thesis involves the study of introducing passive exit flexibility in a two dimensional starting jet. This is relevant to various biological flows like propulsion of aquatic creatures (jellyfish, squid etc.) and flow in the human heart. In the present study we introduce exit flexibility in two ways. The first method was by hinging rigid plates at the channel exit and the second was by attaching deformable flaps at the exit. In the hinged flaps cases, the experimental arrangement closely approximates the limiting case of a free-to-rotate rigid flap with negligible structural stiffness, damping and flap inertia; these limiting structural properties permitting the largest flap openings. In the deformable flaps cases, the flap’s stiffness (or its flexural rigidity EI) becomes an important parameter. In both cases, the initial condition was such that the flaps were parallel to the channel walls. With this, a piston was pushed in a controlled manner to form the starting jet. Using this arrangement, we start the flow and visualize the flap kinematics and make flow field measurements. A number of parameters were varied which include the piston speed, the flap length and the flap stiffness (in case of the deformable flaps). In the hinged rigid flaps cases, the typical motion of the flaps involves a rapid opening with flow initiation and a subsequent more gradual return to its initial position, which occurs while the piston is still moving. The initial opening of the flaps can be attributed to an excess pressure that develops in the channel when the flow starts, due to the acceleration that has to be imparted to the fluid slug between the flaps. In the case with flaps, additional pairs of vortices are formed because of the motion of the flaps and a complete redistribution of vorticity is observed. The length of the flaps is found to significantly affect flap kinematics when plotted using the conventional time scale L/d. However, with a newly defined time-scale based on the flap length (L/Lf ), we find a good collapse of all the measured flap motions irrespective of flap length and piston velocity for an impulsively started piston motion. The maximum opening angle in all these impulsive velocity program cases, irrespective of the flap length, is found to be close to 15 degrees. Even though the flap kinematics collapses well with L/Lf , there are differences in the distribution of the ejected vorticity even for the same L/Lf . In the deformable flap cases, the initial excess pressure in the flap region causes the flaps to bulge outwards. The size of the bulge grows in size, as well as moves outwards as the flow develops and the flaps open out to reach their maximum opening. Thereafter, the flaps start returning to their initial straight position and remain there as long as the piston is in motion. Once the piston stops, the flaps collapse inwards and the two flap tips touch each other. It was found that the flap’s flexural rigidity played an important role in the kinematics. We define a new time scale (t ) based on the flexural rigidity of the flaps (EI) and the flap length (Lf ). Using this new time scale, we find that the time taken to reach the maximum bulge (t* 0.03) and the time taken to reach the maximum opening (t* 0.1) were approximately similar across various flap stiffness and flap length cases. The motion of the flaps results in the formation of additional pairs of vortices. Interestingly, the total final circulation remains almost the same as that of a rigid exit case, for all the flap stiffness and flap lengths studied. However, the final fluid impulse (after all the fluid had come out of the flap region) was always higher in the flap cases as compared to the rigid exit case because of vorticity redistribution. The rate at which the impulse increases was also higher in most flap cases. The final impulse values were as large as 1.8 times the rigid exit case. Since the time rate of change of impulse is linked with force, the measurements suggest that introduction of flexible flaps at the exit could result in better propulsion performances for a system using starting jets. The work carried out in this thesis has shown that by attaching flexible flaps at the exit of an unsteady starting jet, dramatic changes can be made to the flow field. The coupled kinematics of the flaps with the flow dynamics led to desirable changes in the flow. Although the flaps introduced in this work are idealized and may not represent the kind of flexibility we encounter in biological systems, it gives us a better understanding of the importance of exit flexibility in these kinds of flows.

Dans les 50 dernières années, les avancées dans le domaine de la protection des plantes ont contribué à augmenter les rendements et à assurer une large production. Facile à utiliser et plutôt bon marché à l’époque, les pesticides ont prouvé leur efficacité. Cependant, quand ils sont appliqués aux cultures, une partie du produit n’atteint pas sa cible et est perdu dans l’air ou au sol. Par conséquent, des efforts ont été consentis pour améliorer leur efficacité et leur innocuité sanitaire, souvent grâce à des lois environnementales internationales. Les produits sont appliqués à partir de matériels combinant type de buse/pression induisant des gammes de vitesses et de tailles de gouttelettes très diverses (Chapitre 2). Une mesure simultanée de ces vitesses et tailles est ainsi d’une grande importance dans le processus de pulvérisation. Il existe de nombreuses méthodes pour la mesure des caractéristiques des gouttelettes qui peuvent être divisées en trois catégories: mécaniques, électriques et optiques. Ces dernières apparaissent comme les plus pertinentes puisqu’étant non invasives et en perturbant donc pas le processus de pulvérisation. Les améliorations récentes dans le domaine du traitement des images et la réduction du coût des systèmes d’imagerie ont ainsi accru l’intérêt des techniques d’imagerie rapide pour les applications agricoles telles que la pulvérisation de pesticides. Cette thèse s’est donc focalisée sur le développement d’une telle technique pour la caractérisation des sprays (micro et macro). Les travaux effectués ont permis de démontrer que les caractéristiques d’un jet de pesticides peuvent être correctement et précisément mesurées par des techniques d’imagerie non-invasives couplées à des traitements spécifiques. Les travaux à venir consisteraient notamment en l’amélioration de la précision des mesures effectuées: précision sub-pixellique, calcul des profondeurs de champ, mesure de particules non sphériques. / In recent years, advances in plant protection have contributed considerably to increasing crop yields in a sustainable way. Easy to apply and rather inexpensive, pesticides have proven to be very efficient. However, when pesticides are applied to crops some of the spray may not reach the target, but move outside the intended spray area. This can cause serious economic and environmental problems. Most of the pesticides are applied using agricultural sprayers. These sprayers use hydraulic nozzles which break the liquid into droplets with a wide range of droplet sizes and velocities and determine the spray pattern. Small droplets are prone to wind drift, while large droplets can runoff from the target surface and deposit on the soil. Therefore, efforts are being undertaken to come to a more sustainable use of pesticides which is more and more regulated by international environmental laws. One of the main challenges is to reduce spray losses and maximize spray deposition and efficacy by improving the spray characteristics and the spray application process. Because mechanisms of droplets leaving a hydraulic spray nozzle are very complex and difficult to quantify or model, there is a need for accurate quantification techniques. The recent improvements in digital image processing, sensitivity of imaging systems and cost reduction have increased the interest in high-speed (HS) imaging techniques for agricultural applications in general and for pesticide applications in specific. This thesis focused on the development and application of high speed imaging techniques to measure micro (droplet size and velocity) and macro (spray angle and shape, liquid sheet length) spray characteristics.The general aim was to show that the spray characteristics from agricultural spray nozzles can be measured correctly with the developed imaging techniques in a non-intrusive way. After a review of the spray application process and techniques for spray characterization (Chapter 2), two image acquisition systems were developed in Chapter 3 based on single droplet experiments using a high speed camera and a piezoelectric droplet generator. 58 combinations of lenses, light sources, diffusers, and exposure times were tested using shadowgraph (background) imaging and evaluated based on image quality parameters (signal to noise rate, entropy ratio and contrast ratio), light stability and overexposure ratio and the accuracy of the droplet size measurement. These resulted into development of two image acquisition systems for measuring the macro and micro spray characteristics. The HS camera with a macro video zoom lens at a working distance of 143 mm with a larger field of view (FOV) of 88 mm x 110 mm in combination with a halogen spotlight and a diffuser was selected for measuring the macro spray characteristics (spray angle, spray shape and liquid sheet length). The optimal set-up for measuring micro spray characteristics (droplet size and velocity) consisted of a high speed camera with a 6 μs exposure time, a microscope lens at a working distance of 430 mm resulting in a FOV of 10.5 mm x 8.4 mm, and a xenon light source used as a backlight without diffuser. In Chapter 4 image analysis and processing algorithms were developed for measuring single droplet characteristics (size and velocity) and different approaches for image segmentation were presented. With the set-up for micro spray characterization and using these dedicated image analysis algorithms (Chapter 4), measurements using a single droplet generator in droplet on demand (DOD) and continuous mode were performed in Chapter 5. The effects of the operating parameters, including voltage pulse width and pulse amplitude with 4 nozzle orifice sizes (261 μm, 123 μm, 87 μm and 67 μm) on droplet diameter and droplet velocity have been characterized (...)