In-line Water Research Articles

Bacterial host and reporter gene optimization for genetically encoded whole cell biosensors.

Whole-cell biosensors based on reporter genes allow detection of toxic metals in water with high selectivity and sensitivity under laboratory conditions; nevertheless, their transfer to a commercial inline water analyzer requires specific adaptation and optimization to field conditions as well as economical considerations. We focused here on both the influence of the bacterial host and the choice of the reporter gene by following the responses of global toxicity biosensors based on constitutive bacterial promoters as well as arsenite biosensors based on the arsenite-inducible Pars promoter. We observed important variations of the bioluminescence emission levels in five different Escherichia coli strains harboring two different lux-based biosensors, suggesting that the best host strain has to be empirically selected for each new biosensor under construction. We also investigated the bioluminescence reporter gene system transferred into Deinococcus deserti, an environmental, desiccation- and radiation-tolerant bacterium that would reduce the manufacturing costs of bacterial biosensors for commercial water analyzers and open the field of biodetection in radioactive environments. We thus successfully obtained a cell survival biosensor and a metal biosensor able to detect a concentration as low as 100 nM of arsenite in D. deserti. We demonstrated that the arsenite biosensor resisted desiccation and remained functional after 7days stored in air-dried D. deserti cells. We also report here the use of a new near-infrared (NIR) fluorescent reporter candidate, a bacteriophytochrome from the magnetotactic bacterium Magnetospirillum magneticum AMB-1, which showed a NIR fluorescent signal that remained optimal despite increasing sample turbidity, while in similar conditions, a drastic loss of the lux-based biosensors signal was observed.

A bioluminescent arsenite biosensor designed for inline water analyzer.

Whole-cell biosensors based on the reporter gene system can offer rapid detection of trace levels of organic or metallic compounds in water. They are well characterized in laboratory conditions, but their transfer into technological devices for the surveillance of water networks remains at a conceptual level. The development of a semi-autonomous inline water analyzer stumbles across the conservation of the bacterial biosensors over a period of time compatible with the autonomy requested by the end-user while maintaining a satisfactory sensitivity, specificity, and time response. We focused here on assessing the effect of lyophilization on two biosensors based on the reporter gene system and hosted in Escherichia coli. The reporter gene used here is the entire bacterial luciferase lux operon (luxCDABE) for an autonomous bioluminescence emission without the need to add any substrate. In the cell-survival biosensor that is used to determine the overall fitness of the bacteria when mixed with the water sample, lux expression is driven by a constitutive E. coli promoter PrpoD. In the arsenite biosensor, the arsenite-inducible promoter P ars involved in arsenite resistance in E. coli controls lux expression. Evaluation of the shelf life of these lyophilized biosensors kept at 4°C over a year evidenced that about 40% of the lyophilized cells can be revived in such storage conditions. The performances of the lyophilized biosensor after 7months in storage are maintained, with a detection limit of 0.2μM arsenite for a response in about an hour with good reproducibility. These results pave the way to the use in tandem of both biosensors (one for general toxicity and one for arsenite contamination) as consumables of an autonomous analyzer in the field.

Multisensor Portable Meter for Environmental Applications

In recent years, the development of information and communication technologies has notably improved the water management processes, but the technologies for water quality control still leave much scope for improvement. Specially, in situ and inline water monitoring has an increasing interest in order to take decisions at real time. The main drawbacks of the current portable meters are their high cost and their high power consumption. In this paper, it is proposed a portable compact meter for measuring simultaneously oxidation–reduction potential, conductivity, temperature, and amperometric parameters like chlorine. This system includes microsensors fabricated with microelectronic technologies, and a commercial temperature sensor, all them allowing a very low power consumption. Validation of the system has been carried out using standard solutions and comparing the results with commercial sensors. The response characteristics of sensors, in terms of sensitivity and repeatability, showed good agreement with those obtained with standard equipment using the same microelectrodes.

Raman spectroscopy for in-line water quality monitoring--instrumentation and potential.

Worldwide, the access to safe drinking water is a huge problem. In fact, the number of persons without safe drinking water is increasing, even though it is an essential ingredient for human health and development. The enormity of the problem also makes it a critical environmental and public health issue. Therefore, there is a critical need for easy-to-use, compact and sensitive techniques for water quality monitoring. Raman spectroscopy has been a very powerful technique to characterize chemical composition and has been applied to many areas, including chemistry, food, material science or pharmaceuticals. The development of advanced Raman techniques and improvements in instrumentation, has significantly improved the performance of modern Raman spectrometers so that it can now be used for detection of low concentrations of chemicals such as in-line monitoring of chemical and pharmaceutical contaminants in water. This paper briefly introduces the fundamentals of Raman spectroscopy, reviews the development of Raman instrumentations and discusses advanced and potential Raman techniques for in-line water quality monitoring.

Effect of Methanol Additive with LPG in Three Cylinder Four Stroke S.I. Engine

LPG is a mixture of gas, mainly propane and butane. It is commonly used as a fuel for cooking and as a transportation fuel. It is normally created as a by-product of petroleum refining and from the production of Natural Gas. An experiment is conducted to obtain the operating characteristics of the four stroke three cylinder inline water cooled spark ignition engine operated with LPG and methanol. The engine is started with LPG and methanol with various ratios at constant volume rate in the vaporizer. Solenoid valve was used to allow either LPG or petrol in the carburetor. The LPG supplied through the vaporizer and the quantity is metered by hanging type weighing scale. The additives are added with LPG before supplied to the vaporizer. The performance characteristics of engine were analyzed using petrol with increase in load. Further the engine run with LPG and adjusts the flow based on the mixing of additives. The best ratio of additives can be selected based on the experimental results obtained in the engine.The findings of the present research work suggest that optimum % of methanol as additive to increase the overall performance and to reduce the emission levels.

Design and heat flow analysis of a commercial energy efficient in-line water heating system

In this paper, the authors provide the design, heat flow analysis and pressure analysis of a commercial energy efficient in-line water heating system in South Africa. The designed commercial in-line water heating system captures the energy consumption, flow rate, temperature and pressure during operation and accordingly responds on these values to increase the energy efficiency of the system. The user is constantly aware of the energy consumption and cost during operation and can choose to switch to a more economical setting to conserve energy. A central processor with PID control was used to optimize the energy consumption of the in-line water heating system. An overview on the design and results of the heat flow analysis and pressure analysis are provided.

Efficiency and cost analysis of a designed in-line water heating system compared to a conventional water heating system in South Africa

In this paper, the authors compares the efficiency and cost of a designed in-line water heating system with a conventional water heating system (geyser) in South Africa. The paper provides an overview on water heating systems and heating elements and provides the typical water consumption required by an average household in South Africa. A summary on the design of the in-line water heating system together with a system cost analysis is provided. The designed in-line water heating system takes the energy consumption, temperature and pressure into account during operation. The energy consumption and cost of the designed in-line water heating system is compared to a conventional water geyser. A cost analysis on the designed in-line water heating system, heat pumps and solar water heating systems are also provided. The energy consumption results showed that the conventional water geyser on average consumes 2.5% more energy to heat one litre of water from 15 °C to 60 °C, than the designed in-line water heating system to supply one litre of water at 60°C.

Economic benefits of controlled tile drainage: Watershed Evaluation of Beneficial Management Practices, South Nation River basin, Ontario

Controlled tile drainage (CTD) is an agricultural beneficial management practice that can boost crop yields and reduce water and nutrient export from fields to surface water systems. This study examined on-farm incremental net benefits resulting from retrofitting existing tile drainage systems with inline water level control structures that control tile drainage. Corn and soybean yields (2005–2009) were respectively about 3 and 4% higher from CTD fields relative to conventionally drained fields at an experimental watershed associated with the Watershed Evaluation of Beneficial Management Practices (WEBs) program located in the South Nation river basin in eastern Ontario. The marginal cost of CTD employed in this experimental watershed was ∼Can (2006) $30 ha−1. The benefit–cost ratio was 2.6 for corn and 1.6 for soybean. A crude estimate of a payback period (without cost share) was from 3 to 4 years. Assuming all cropland in the entire South Nation river watershed where CTD is suitable, will be under CTD, the net present value of this practice is estimated to yield on farm annually about $(2006) 4 million for both crops. A crude estimate of non-user off-farm benefits of implementing CTD in this manner was ∼$0.4 million per year.

Usefulness of Non-Chemical Water Conditioners for Managing Turfgrasses and their Rootzones

Physical water conditioning products have been used on golf courses to improve turfgrass quality, improve rootzone salinity, and to reduce irrigation water use. A four-year study was conducted at New Mexico State University to investigate the effects of non-chemical in-line water conditioners (two catalytic, one magnetic, one hydro-electric, and a control treatment) on turfgrass establishment, and on turfgrass quality and rootzone salinity of a perennial ryegrass stand. Conditioning treatments were applied under potable [Electrical conductivity (EC) = 0.6 dS/m] and saline (EC = 3.1 dS/m) irrigation. Conditioning treatments did not affect perennial ryegrass establishment, only saline irrigation delayed establishment. Turfgrass quality on control plots did not differ from conditioner treated plots for both water qualities on all but one sampling date. The rootzone salinity results were inconclusive; no clear consistent trends were found for individual measured parameters. After four years of research, a consistent positive impact of these conditioning units on turf quality and rootzone salinity could not be substantiated.

A molecular method to assess Phytophthora diversity in environmental samples

Current molecular detection methods for the genus Phytophthora are specific to a few key species rather than the whole genus and this is a recognized weakness of protocols for ecological studies and international plant health legislation. In the present study a molecular approach was developed to detect Phytophthora species in soil and water samples using novel sets of genus-specific primers designed against the internal transcribed spacer (ITS) regions. Two different rDNA primer sets were tested: one assay amplified a long product including the ITS1, 5.8S and ITS2 regions (LP) and the other a shorter product including the ITS1 only (SP). Both assays specifically amplified products from Phytophthora species without cross-reaction with the related Pythium s. lato, however the SP assay proved the more sensitive and reliable. The method was validated using woodland soil and stream water from Invergowrie, Scotland. On-site use of a knapsack sprayer and in-line water filters proved more rapid and effective than centrifugation at sampling Phytophthora propagules. A total of 15 different Phytophthora phylotypes were identified which clustered within the reported ITS-clades 1, 2, 3, 6, 7 and 8. The range and type of the sequences detected varied from sample to sample and up to three and five different Phytophthora phylotypes were detected within a single sample of soil or water, respectively. The most frequently detected sequences were related to members of ITS-clade 6 (i.e. P. gonapodyides-like). The new method proved very effective at discriminating multiple species in a given sample and can also detect as yet unknown species. The reported primers and methods will prove valuable for ecological studies, biosecurity and commercial plant, soil or water (e.g. irrigation water) testing as well as the wider metagenomic sampling of this fascinating component of microbial pathogen diversity.

In-Line-Water-Separation Prototype Development and Testing

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper SPE 137967, ’Inline Water Separation (IWS) Field Prototype Development and Testing,’ by J.J. Xiao, SPE, and Ramsey White, Saudi Aramco, and Shoubo Wang and Luis Gomez, Multiphase Systems Integration, originally prepared for the 2010 SPE Abu Dhabi International Petroleum Exhibition and Conference, Abu Dhabi, UAE, 1-4 November. The paper has not been peer reviewed. A compact multiphase in-line-water-separation (IWS) field prototype system has been developed and tested. The system consists of a gas/liquid cylindrical cyclone (GLCC), a liquid/liquid pipe separator (LLPS), a liquid/liquid cylindrical cyclone (LLCC), and two-stage liquid/liquid hydrocyclones (LLHCs). The function of the system is to separate a significant portion of the produced water from a production stream while the remaining production fluids are sent to existing processing facilities. Introduction As oil fields mature, more water is produced with the oil and gas production. This is especially true when water injection is used to maintain reservoir pressure and increase oil recovery. A common production-water-handling strategy is centralized processing. In this scheme, production from individual wells is gathered to manifolds through flowlines and is transported to the gas-/oil-separation plant (GOSP) through large-diameter trunklines. At the GOSP, separation and processing of oil, gas, and water take place with large conventional vessels. The processed water is either disposed of at nearby water-disposal wells or sent back to the field for water reinjection into the reservoir. With increasing water production, several issues can develop: Water volume exceeds water-handling capacity of the GOSP, which can cause processed water to be off specification. The off-specification water in turn can lead to a decline in water injectivity, which may require regular stimulation treatments. Upgrade or expansion of GOSP water-handling capacity with conventional bulky separation systems can be costly. Existing gathering systems can become a bottleneck to oil production. To maintain oil production, the total fluid produced will increase as the water cut increases, and the gathering-system capacity will become a limiting factor. Laying extra flowlines or trunklines can be expensive, especially offshore. Wells can cease to produce because of increasing system backpressure as a result of the increasing water volume being transported through the gathering systems. Higher water production leads to higher chemical use (demulsifers and corrosion inhibitors) and, hence, higher processing cost. In addition, energy consumption will increase to transport large quantities of water from the field to the GOSP and then from the GOSP back for reinjection into the wells in the field. A number of methods are used to reduce the quantity of water produced to the surface. These methods include restricted production, cyclic production, mechanical or chemical water shutoff, and short-radius horizontal drilling. For new wells, the use of production equalizers and smart completions also can be viewed broadly as a way to control water production. The next-best place to handle water production is in the wellbore. However, downhole oil/water separation and reinjection still remain a challenge even after 20 years of industry research and development.

Techbits: Efficiency Improvements for Facilities Focus of Workshop

Techbits Innovations aimed at improving efficiencies in surface facilities were the focus of an SPE Applied Technology Workshop (ATW) titled "Surface Facilities: Improving Efficiencies in Production, Energy Conservation, CO2 Reduction, and Waste Management" held in Dubai. More than 50 attendees from 25 companies and 16 countries reviewed the challenges of oil/water/gas separation, conservation, emission, and waste management in the backdrop of increasingly stringent regulatory requirements. Abbas Ahmed Yousef, field manager for Adco's Bab field, opened the ATW with a keynote address focusing on the means to improve surface-facility efficiency, emphasizing the need for operators to adopt more enhanced oil recovery (EOR) techniques to improve production efficiencies. He also touched on the importance of energy conservation and emissions and waste management, particularly as producing fields mature. Oil/Water/Gas Separation and Handling In the ATW's first session, Ahmed Abdulmajeed of Saudi Aramco discussed process enhancements in gas/oil separation plants within his company. He reviewed how a new mixing valve for wash water going to desalters was able to reduce wash water consumption from 50 to 30 gallons per minute, resulting in more than 10 million gallons of water savings over one year. He also discussed how the implementation of a smokeless, high-pressure air-assisted flare system, which employs a new flare-tip design and additional flare-tip shield, provides for better gas combustion. Saudi Aramco is also testing an in-line water separator that promises to remove approximately 70–80% of water without the need to treat in a gas/oil separation plant and with quality in the range of 22–35 ppm of oil in water. Alexander de Kruijf of Petroleum Development Oman (PDO) discussed the pitfalls of improper oil and gas sampling and made predictions on future process-equipment design. Inaccurate measurement of H2S in one PDO application led to deteriorating sales gas quality, with H2S concentrations reaching 5 ppm. The result was 4 months of deferment equivalent to approximately 100,000 BOPD. To prevent acid corrosion in equipment, de Kruijf stressed the importance of routinely measuring for organic acid, using corrosion-resistant alloys with increased corrosion allowances, and implementing organic pH neutralizers. In general, he advised that production chemistry programs should be an integral part of a project's process. Oliver Garnier of Total reviewed a strategy to maintain production from his company's mature Abu Al-Bukhoosh field. The field has been producing since 1974, and present production is 15,000 BOPD with an average basic sediment and water (BS&W) of 86%. By implementing improvements, including increasing the impeller size in the gas recovery compressor, closing wells with too high a BS&W, optimizing well productivity by using multiphase flowmeters, and implementing de-emulsifier injection with gas lift, Total has managed to level the oil production potential to above 16,000 BOPD since 2007.

Molecular Dynamics Simulations Of The Hydrolysis Transition State Intermediate In Myosin

We have used molecular dynamics simulations to analyze the nucleotide site of myosin and its interaction with ATP and a catalytic water. Simulations used the Dictyostelium myosin ADP•VO4 x-ray crystal structure. This structure is widely hypothesized to be an analog of the hydrolysis transition state intermediate for an in-line water attack on the γ-phosphate position. The trigonal bi-pyramidal VO4 moiety was replaced by PO3 covalently bound to ADP and a water molecule oxygen. Surprisingly, the MD simulation indicated that the x-ray structure was not capable of controlling the position of the modeled attacking water as required for hydrolysis. Instead the water molecule rattled around a catalytic pocket formed by the γ-phosphate of ATP, elements of switch 1, switch 2, and the salt-bridge between R238 and E459. The salt-bridge has been postulated to serve to help stabilize the closed conformation of switch 2. The simulated double alanine R238A/E459A mutation eliminated this salt-bridge. There was little resulting change in the conformation of switch 2 (0.55A r.m.s. deviation, Cα-Cα, a.a. D454-L495) and the crucial hydrogen bond distance between the backbone amide of G457 and the γ-phosphate oxygen of ATP increased from 1.9A to only 2.0A in the mutated structure. However, the modeled catalytic water rapidly escaped from the catalytic pocket in the mutated myosin. Thus the simulations suggest that the closed-switch 2 structure is stabilized by a number of interactions in addition to the salt-bridge. The function of the salt-bridge is to serve as a lid to sequester water in the catalytic pocket.

Water Intake and Dry Matter Intake Changes as a Feeding Management Tool and Indicator of Health and Estrus Status in Dairy Cows

This study investigates whether dry matter (DM) or water intake is affected by the presence of disease or estrus in dairy cows and whether water intake can serve as an accurate substitute for monitoring changes in DM intake (DMI). A combined cumulative sum (CUSUM) and Shewhart monitoring scheme is proposed to detect DMI changes and emerging disease or estrus. Daily readings from 35 inline water meters for 35 water cups in a tie-stall barn at the University of Minnesota were collected from September 2005 until June 2006. Two cows were assigned to each water cup. Individual DMI were recorded for each of the 70 cows on the study. All drug or hoof treatments administered to the cows along with breeding and calving events were also recorded and classified as 1 of the following 6 event categories: estrus, calving, mastitis, fever, hoof treatment, and other. Analysis of covariance was used to identify factors significantly changing intake. Only the first 150 d in milk (DIM) were considered in the analysis. Six event categories plus DIM, ambient temperature, relative humidity, and parity were entered as independents into the model. Calving, primiparity, and health events categorized as “other” were associated with decreased DM and water intake. Mastitis decreased DMI and fever negatively affected water intake. Both intakes increased with DIM, and water intake decreased with increase in humidity. Covariance analysis was used to investigate the relationship between DMI and water intake. In model 1, analysis was done for a pair of cows, whereas model 2 modeled DMI of the whole group of 70 cows. Water intake, ambient temperature, humidity, and DIM were entered as independents in both models and parity was entered in model 1. Polynomial models and 2-way interactions were also considered. Water intake, ambient temperature, DIM, and DIM2 were kept in final models 1 and 2, and parity was kept in model 1. Final models for cow pairs and a group of 70 cows resulted in R2 of 0.50 and 0.82, respectively. The proposed CUSUM-Shewhart DMI monitoring scheme successfully detected emerging disease even in the first week of lactation. Monitoring water intake can serve as an alternative to measurements of DMI for groups of cows and has the potential of predicting change in individual cow health and estrus status.

Inline Concentration Monitoring of Binary Liquid Mixtures in the Presence of a Dispersed Gas Phase with a Modified Speed of Sound Immersion Probe

AbstractA commercial speed of sound (SOS) immersion probe has been modified in order to permit concentration measurements of liquid mixtures in the presence of dispersed gas phases. Experiments were performed in which water was removed from a polymer/water mixture via evaporation and stripping in mixed vessels of different flow patterns. The original and modified SOS immersion probe was used to monitor the water concentration. In the stripping stage, where a persistent gas phase of high volume fraction is generated, the original SOS immersion probe fails to measure the water concentration. This drawback has been successfully eliminated by means of a special SOS probe housing. The modified SOS immersion probe showed reliable inline water concentration monitoring for directed (draft tube reactor) and undirected flow pattern (ordinary stirred reactor) under boiling and stripping conditions.

Estimating uncertainty of flow measurement for the in-situ calibration of large water meters

A methodology for the establishment of an in-situ calibration approach that makes measurement results more accurate has been determined from previous research. The quality system derived for this in-situ calibration approach facilitates confidence by stakeholders in the statements of uncertainty of flow measurement for existing large in-line water meters. The quality system is outlined in a quality manual that is the core document used for the purposes of obtaining accreditation from a country’s national accreditation body. Some important components of uncertainty of measurement have been identified, as well as guidance as to how they can be minimised when applying the in-situ calibration methodology. When the regular in-situ calibration of large water meters is included as an integral part of sustainable water management practice, the benefits will include minimising non-physical (apparent) water losses, improved financial accountability and optimal decision-making.

Metallurgical investigation into the causes of premature failure of high-carbon steel wire rods during hot rolling

Wire rods of high-carbon steel, in sizes ranging between 5.5 and 14 mm, are normally produced from continuously cast billets by hot rolling in a wire rod mill. These wire rods are usually supplied to wire drawing plants in either the hot rolled or the controlled-cooled condition. The microstructure of the hot rolled wire rods is a coarse lamellar pearlite and is unsuitable for large reductions by cold drawing. In contrast, the microstructure of controlled-cooled wire rods is a relatively fine pearlite, developed as a consequence of in-line water and forced-air cooling, and is suitable for large reductions by cold drawing. Although wire rod breakages in modern-day mills are comparatively rare, they nonetheless may take place due to a variety of factors. The failure of wire rods, hot rolled or controlled cooled, may occur as a result of improper rolling schedule, cobbles, sudden mill stoppages and/or accelerations, and processing inadequacies that lead to the formation of inappropriate microstructures. A comprehensive metallurgical investigation may therefore be necessary to discover the genesis of wire rod breakages during rolling and/or finish cooling operations.

The Skp1 Prolyl Hydroxylase from Dictyostelium Is Related to the Hypoxia-inducible Factor-α Class of Animal Prolyl 4-Hydroxylases

Skp1 is a cytoplasmic and nuclear protein of eukaryotes best known as an adaptor in SCF ubiquitin-protein isopeptide ligases. In Dictyostelium, Skp1 is subject to 4-hydroxylation at Pro(143) and subsequent O-glycosylation by alpha-linked GlcNAc and other sugars. Soluble cytosolic extracts have Skp1 prolyl 4-hydroxylase (P4H) activity, which can be measured based on hydroxylation-dependent transfer of [(3)H]GlcNAc to recombinant Skp1 by recombinant (Skp1-protein)-hydroxyproline alpha-N-acetyl-d-glucosaminyltransferase. The Dictyostelium Skp1 P4H gene (phyA) was predicted using a bioinformatics approach, and the expected enzyme activity was confirmed by expression of phyA cDNA in Escherichia coli. The purified recombinant enzyme (P4H1) was dependent on physiological concentrations of O(2), alpha-ketoglutarate, and ascorbate and was inhibited by CoCl(2), 3,4-dihydroxybenzoate, and 3,4-dihydroxyphenyl acetate, as observed for known animal cytoplasmic P4Hs of the hypoxia-inducible factor-alpha (HIFalpha) class. Overexpression of phyA cDNA in Dictyostelium yielded increased enzyme activity in a soluble cytosolic extract. Disruption of the phyA locus by homologous recombination resulted in loss of detectable activity in extracts and blocked hydroxylation-dependent glycosylation of Skp1 based on molecular weight analysis by SDS-PAGE, demonstrating a requirement for P4H1 in vivo. The sequence and functional similarities of P4H1 to animal HIFalpha-type P4Hs suggest that hydroxylation of Skp1 may, like that of animal HIFalpha, be regulated by availability of O(2), alpha-ketoglutarate, and ascorbate, which might exert novel control over Skp1 glycosylation.

In situ calibration of a low-level, in-line, flow liquid scintillation analyzer.

A new method to calibrate a flow liquid scintillation detector in an in-line waste water monitor was developed and its operation was verified. The liquid scintillation detector for detecting low energy beta emitters was one of three detectors of the monitor that aimed to analyze radionuclide concentrations in the waste water before draining it into sewer. To calibrate the liquid scintillation detector, a 20-cm3 calibration vial containing a reference solution was connected to the water sampling channel with a three-way valve. Ten measurements needed to define a quench correction curve required only 200 cm3 solution. The counting efficiencies of the liquid scintillation detector for 3H and for 14C under the average quenching level of the waste waters were estimated at 27% and 58%, respectively. The calibration using the vial took into account the sampling and mixing system, which would not be the case with sealed quenched standards. Although active solution was used, the method was simple, generated little active waste, had low possibility of contamination, and reduced costs and labor for the calibration.

K-2231 油燃焼ボイラなどにおける噴霧挙動の数値解析のための基礎実験研究 : 気流中における液滴の分裂挙動の相互干渉(S29-3 地域エネルギーシステムにおける小型発電技術の動向(3))(S29 地域エネルギーシステムにおける小型発電技術の動向)

Interaction between liquid droplets under breakup in gas stream was investigated experimentally, to obtain basic knowledge for developing numerical simulation model of twin-fluid liquid atomization. Pair of inline water droplets was dropped into air stream passing through an orifice, and breakup processes of droplets were observed using a high-speed video camera. When dimensionless distance between droplets was larger than about 3, each droplet broke up as a single droplet. However the upstream droplet affected breakup behavior of the downstream droplet when dimensionless distance was small. There are three representative types of interaction. Critical condition for the interaction was investigated and the mechanism of interaction was discussed. Experimental data on droplet acceleration were compared with numerical results based on drop drag and breakup model. It was shown that the conventional numerical model could not estimate acceleration as well as deformation of droplets accurately when droplet number density was high.