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Artykuły w czasopismach na temat "Rotational Irrigation Delivery System"
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Zardari, Noor ul Hassan, i Ian Cordery. "Estimating the effectiveness of a rotational irrigation delivery system: A case study from Pakistan". Irrigation and Drainage 59, nr 3 (13.03.2009): 277–90. http://dx.doi.org/10.1002/ird.483.
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Bhadra, Aditi, Arnab Bandyopadhyay, Rajendra Singh i Narendra S. Raghuwanshi. "An Alternative Rotational Delivery Schedule for Improved Performance of Reservoir-based Canal Irrigation System". Water Resources Management 24, nr 13 (12.03.2010): 3679–700. http://dx.doi.org/10.1007/s11269-010-9626-8.
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Guler, Huseyin, Zhihong Zhang, Heping Zhu, Matthew Grieshop i Mark A. Ledebuhr. "Spray Characteristics of Rotary Micro Sprinkler Nozzles Used in Orchard Pesticide Delivery". Transactions of the ASABE 63, nr 6 (2020): 1845–53. http://dx.doi.org/10.13031/trans.13445.
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HighlightsDroplet sizes were determined for rotary micro sprinkler nozzles used in solid set canopy delivery systems.An empirical multiple-variable model was developed to predict volume median diameters in spray patterns.Sprinkler nozzles produced medium to coarse droplets to minimize pesticide drift in orchards and trellised systems.Droplet size information can be used to select optimal nozzles for either irrigation or pesticide delivery systems.Abstract. Rotary micro sprinkler nozzles can be used for both irrigation and pesticide applications in orchard systems, but little to no information is available on their droplet size distributions. In this study, the droplet size distributions were investigated and described for rotary micro sprinkler nozzles with five different orifice diameters. A particle/droplet laser image analysis system was used to measure droplet spectra at two pressures (207 and 310 kPa) and two radial distances (0.25 and 0.85 m) from the sprinkler nozzle center. Nozzle orifice sizes, rotational speeds, and flow rates were also measured. Droplet sizes varied with the orifice size, operating pressure, and sampling location. Spiral-shaped spray patterns formed due to the spinning discharge port, within which droplet densities varied with location, orifice diameter, and operating pressure. The volume medium diameters (Dv0.5) for green-black, orange-blue, black-black, blue-black, and red-gray nozzles were respectively 317, 338, 379, 352, and 218 µm at 207 kPa and 283, 250, 283, 270, and 222 µm at 310 kPa. An empirical multiple-variable regression model was developed to predict Dv0.5 in the spray patterns discharged from the nozzles. Test results demonstrated that the rotary micro sprinkler nozzles produced medium to coarse droplets that could be used to minimize spray drift while maintaining efficacy in orchard pesticide applications. Keywords: Chemical application, Droplet size, Irrigation, Rotary nozzle, Spray drift reduction.
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Kadbhane, Sharad J., i Vivek L. Manekar. "An experimental study on the grape orchard: Effects comparison of two irrigation systems". Journal of Water and Land Development 32, nr 1 (1.03.2017): 41–51. http://dx.doi.org/10.1515/jwld-2017-0005.
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Abstract Table grape (Vitis vinifera cultivars) is a major cash crop in the Nashik district of India, which requires irrigation water throughout the year as per demand instantly. Canal irrigation is the adopted irrigation systems in the study area, but canal irrigation has got several serious disadvantages, such as mismatching rotation schedules and crop water demands, water allotment system and restrictions on the use of efficient irrigation methods. The storing the canal water in the farm pond instead of directly applying to the field using the free flooding method is alternate solution to overcome the disadvantages of the canal irrigation system. Once the canal water storing in the pond, it increases the possibilities to use the advance irrigation system like drip, subsurface, sprinkler etc. to enhance water use efficiency. The comparative study between the canal water directly applying for the field and canal water storing in the farm pond then use for irrigation, executed through the field experiments carried out on the grape orchard during a period April 2013 to March 2016. Results have been evaluated based on grape yield, water-productivity, berry size, and biomass. Water productivity (kg·m-3) with respect to water delivery to crop through the pond irrigation method was found 37% higher than the canal irrigation method during the study period. Based on the results, this study recommended the use of the farm pond to store the canal water and use it as per crop demand using advance irrigation systems.
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Qureshi, Sarfraz Khan, Zakir Hussain i Zeb-Un-Nisa. "An Assessment of Warabandi (Irrigation Rotation) in Pakistan: A Preliminary Analysis". Pakistan Development Review 33, nr 4II (1.12.1994): 845–55. http://dx.doi.org/10.30541/v33i4iipp.845-855.
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A significant feature of Pakistan's agriculture is that it is served by the Indus irrigation system, which is one of the largest contiguous irrigation systems in the world. The system comprises of the Indus River and its tributaries, three major storage reservoirs, 19 barrages/headworks, 43 canals, and 12 link canals and 43 canals covering about 43,000 chaks or village settlements. The total length of the canal system is about 40,000 miles with over 80,000 water courses, field channels ' and ditches running for another million miles. About 100--106 million acre feet (MAP) of surface irrigation supplies are diverted annually into the canal system. Only 60 percent of this water reaches the farmgate due mainly to low efficiency in the delivery of water. The historical review of the area, production and yield trends shows that agricultural production in the past has increased mainly due to expansion in irrigated acreage while the contribution of changes in yields has been insignificant. In general, agricultural production can be increased by either expanding the irrigated cropped area or by raising the crop yields. It is highly unlikely that Pakistan will be able to satisfy the food needs of the rapidly increasing population through yield increases alone. This means that there ia a need to increase the irrigated cropped area through additional water supplies and by improving the efficiency of water use through using the water resources in a scientific manner.
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Qureshi, Asad Sarwar, i Chris Perry. "Managing Water and Salt for Sustainable Agriculture in the Indus Basin of Pakistan". Sustainability 13, nr 9 (10.05.2021): 5303. http://dx.doi.org/10.3390/su13095303.
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The Indus basin of Pakistan occupies about 16 million ha (Mha) of land. The Indus River and its tributaries are the primary sources of surface water. An estimated 122 km3 of surface water is diverted annually through an extensive canal system to irrigate this land. These surface water supplies are insufficient to meet the crop water requirements for the intensive cropping system practiced in the Indus basin. The shortfall in surface water is met by exploiting groundwater. Currently, about 62 km3 of groundwater is pumped annually by 1.36 million private and public tube wells. About 1.0 million tubewells are working only in the Punjab province. Small private tubewells account for about 80% of the pumped volume. Inadequate water allocation along the irrigation canals allows excessive water use by head-end farmers, resulting in waterlogging. In contrast, the less productive use of erratic supplies by tail-end farmers often results in soil salinity. The major issues faced by irrigated agriculture in Pakistan are low crop yields and water use efficiency, increasing soil salinization, water quality deterioration, and inefficient drainage effluent disposal. Currently, 4.5 Mha (about 30% of the total irrigated area) suffers from adverse salinity levels. Critical governance issues include inequitable water distribution, minimizing the extent to which salt is mobilized, controlling excessive groundwater pumping, and immediate repair and maintenance of the infrastructure. This paper suggests several options to improve governance, water and salt management to support sustainable irrigated agriculture in Pakistan. In saline groundwater areas, the rotational priorities should be reorganized to match the delivery schedules as closely as possible to crop demand, while emphasizing the reliability of irrigation schedules. Wherever possible, public tubewells should pump fresh groundwater into distributaries to increase water availability at the tail ends. Any substantial reform to make water delivery more flexible and responsive would require an amendment to the existing law and reconfiguration of the entire infrastructure, including thousands of kilometers of channels and almost 60,000 outlets to farmer groups. Within the existing political economy of Pakistan, changing the current water allocation and distribution laws without modernizing the infrastructure would be complicated. A realistic reform program should prioritize interventions that do not require amendment of the Acts or reconstruction of the entire system and are relatively inexpensive. If successful, such interventions may provide the basis for further, more substantial reforms. The present rotational water supply system should continue, with investments focusing on lining channels to ensure equitable water distribution and reduce waterlogging at the head ends. Besides that, the reuse of drainage water should be encouraged to minimize disposal volumes. The timely availability of farm inputs can improve individual farmers’ productivity. Farmers will need to have access to new information on improved irrigation management and soil reclamation approaches. Simultaneously, the government should focus more on the management of drainage and salinity.
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Zubaidah, Zubaidah, Alfiansyah Yulianur i Azmeri Azmeri. "KAJIAN PENINGKATAN INTENSITAS TANAM PADA D.I. BARO RAYA SUB D.I. BARO KANAN". Jurnal Teknik Sipil 1, nr 4 (28.02.2018): 1049–58. http://dx.doi.org/10.24815/jts.v1i4.10065.
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Abstract: Baro Raya irrigation area is one of the technical irrigation, source of water for Baro Raya irrigation Channel is Krueng Baro that intercepted through a weir Filter Down (weir Tyrool), with a total area of 11.855 ha irrigation. The purpose of this study were: 1) to find out the large volume / dependable flow that available at the weir, 2) to find out the amount of crop water needs for each alternative, 3) to find out the extents optimum plant that can be irrigated by the available water, 4) by reviewing the dam water balance based on cropping planned, is expected to provide an overview of alternative water balance is obtained. The method used in this research were data collection and data analysis to know dependable flow, water irrigation, cropping pattern and cropping intensity. The existing condition shows that the cropping pattern of rice-paddy-grains, normally cropping intensity in the study area ranged from only a maximum of 183%-231%, with a probability of irrigation water supply capability of MT 1 (rice) 52-84%, MT 2 (rice) 55-71% and MT 3 (pulses) 76-100%, while the study by modifying the cropping pattern into a rice-paddy / crops-rice and accompanied by the water delivery system by rotation, irrigation area Baro Raya Right that has acreage of 8927 ha can be irrigated as a whole even with cropping intensity to a maximum of 300%, with alternative cropping pattern 6 that MT1 (rice, 1 group), MT2 (rice, 2 groups) and MT3 (crops, 1 group), with planting begins in October the 2nd week, these alternatives are the best, classification is only done on MT 2, which is as much as two groups with the type of planting the same namely rice, this condition will minimize social conflict because there is no rotation of the water supply level group, because probability ability of water sources ranging between 84-100%. Abstrak: Daerah irigasi Baro Raya merupakan salah satu daerah irigasi teknis, Sumber air untuk jaringan irigasi Baro Raya adalah Krueng Baro yang disadap melalui sebuah Bendung Saringan Bawah (Bendung Tyrool), dengan luas areal irigasinya 11.855 Ha. Tujuan penelitian ini adalah : 1) Dapat diketahui besarnya volume/kapasitas andalan yang tersedia pada bendung, 2) Dapat diketahui besarnya kebutuhan air tanaman untuk masing-masing alternatif, 3) Dapat diketahui luasan tanaman optimal yang dapat diairi berdasarkan air yang tersedia, 4) Dengan melakukan kajian neraca air bendung berdasarkan pola tanam yang direncanakan, diharapkan dapat memberikan gambaran keseimbangan air dari alternatif yang diperoleh. Metode yang digunakan pada penelitian ini adalah metode pengumpulan data dan analisis data untuk mengetahui debit andalan, kebutuhan air irigasi, pola tanam dan intensitas tanam. Kondisi eksisting menunjukkan bahwa dengan pola tanam padi–padi–palawija, secara normal intensitas tanam yang ada di lokasi studi maksimum hanya berkisar antara 183%-231%, dengan probabilitas kemampuan penyediaan air irigasi sebesar MT 1 (padi) 52-84%, MT 2 (padi) 55-71% dan MT 3 (palawija) 76-100%, sedangkan Kajian dengan cara memodifikasi pola tanam menjadi padi-padi/palawija-padi dan dengan diiringi sistem pemberian air secara rotasi, Daerah Irigasi Baro Raya Kanan yang mempunyai luas areal 8.927 ha dapat diairi secara keseluruhan bahkan dengan intensitas tanam maksimum sebesar 300%, yaitu dengan alternatif pola tanam 6 yakni MT1 (padi, 1 golongan), MT2 (padi,2 golongan) dan MT3 (palawija,1 golongan), dengan masa tanam dimulai pada bulan Oktober minggu ke-2, alternatif ini adalah yang terbaik penggolongan hanya dilakukan pada MT 2, yakni sebanyak 2 golongan dengan jenis tanam yang sama yakni padi, kondisi ini akan memperkecil konflik sosial karena tidak ada rotasi pemberian air ditingkat golongan, sebab probabilitas kemampuan sumber air yang terjadi berkisar antara 84-100%.
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Walton, TJ, S. Heads, RJ Parkinson i TRL Griffiths. "An Improvised Delivery System for Irrigation". Annals of The Royal College of Surgeons of England 90, nr 5 (lipiec 2008): 429–30. http://dx.doi.org/10.1308/rcsann.2008.90.5.429b.
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Gates, Timothy K., Ahdulmohsen A. Alshaikh, Samir I. Ahmed i David J. Molden. "Optimal Irrigation Delivery System Design under Uncertainty". Journal of Irrigation and Drainage Engineering 118, nr 3 (maj 1992): 433–49. http://dx.doi.org/10.1061/(asce)0733-9437(1992)118:3(433).
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Pulido-Calvo, I., J. Roldán, R. López-Luque i J. C. Gutiérrez-Estrada. "Water Delivery System Planning Considering Irrigation Simultaneity". Journal of Irrigation and Drainage Engineering 129, nr 4 (sierpień 2003): 247–55. http://dx.doi.org/10.1061/(asce)0733-9437(2003)129:4(247).
Pełny tekst źródłaRozprawy doktorskie na temat "Rotational Irrigation Delivery System"
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Zardari, Noor-ul-Hassan Civil & Environmental Engineering Faculty of Engineering UNSW. "An improved multicriterion analysis approach to avoid subjectivity in irrigation water allocation decisions". Publisher:University of New South Wales. Civil & Environmental Engineering, 2008. http://handle.unsw.edu.au/1959.4/41300.
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The performance of the century-old irrigation system of Pakistan (i.e. warabandi) has been evaluated using socio-economic data gathered by the author in multiple farmers?? surveys (n=278) conducted in Indus Basin of Pakistan. In the surveyed regions, the warabandi system was performing poorly. In-built rigidity in water allocations was found as main reason behind its poor performance. The results from the farmers?? surveys also revealed that the objective of increasing irrigation water productivity would never be attained under the warabandi arrangements. Hence, a completely new concept that could replace the warabandi system and improve the productivity of limited irrigation water should be introduced. My aim was to find a better way to allocate the scarce water resource between farmers. In this study, I have introduced a new concept for determining water allocations among the farmers, which is based on a multicriterion decision making (MCDM) approach. The consideration of multiple criteria in irrigation water allocations would improve irrigation water productivity. Upon an extensive survey of well-known MCDM methods, I concluded that all previously existing MCDM methods were using subjective inputs, usually from a single modeller, to establish priorities of alternatives and therefore, a predetermined solution could easily be obtained. I have developed an approach based on conjoint analysis which removes that subjectivity from the chosen MCDM method (i.e. ELECTRE). Interval scales and relative importance criteria weights, two usually subjective inputs in ELECTRE, are objectively estimated from the conjoint analysis study. For that purpose, the author designed a conjoint questionnaire and administered it to 62 farmer respondents in face-to-face interviews. Conjoint analysis, which does not appear to have been previously used in water resources or allocation studies, is a method for creating the interval scales and the relative criteria weights objectively from the respondents?? judgements on the importance of conjoint objects. The objective estimation of these two important factors is a completely new development which can assist in the unbiased determination of the best division or allocation of scarce water resources between farmers. The approach is applied, as a demonstration, to a region with nine distributary watercourses to determine which of the distributaries should have the highest priority for allocation of the regional water.
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Zaccaria, Daniele S. A. "A Methodology to Conduct Diagnostic Performance Assessment and Simulation of Deliveries in Large-Scale Pressurized Irrigation Systems". DigitalCommons@USU, 2011. https://digitalcommons.usu.edu/etd/988.
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A methodology was developed to conduct diagnostic performance assessment and simulation of alternative delivery scenarios in pressurized irrigation distribution networks. It consists of three components, an agro-hydrologic model able to forecast peak water demand hydrographs, a hydraulic model with capability of simulating the network behavior under different flow configurations, and a set of performance indicators for conducting assessments of performance achievements relative to specified targets.
As a preliminary work, the current delivery schedule of an existing pressurized irrigation network (system 1) and the resulting effects on crop irrigation management were analyzed by simulating soil water balance and irrigation scheduling at field level. Simulations allowed analyzing the on-farm irrigation management under the current rotation deliveries, and comparing it with an alternative flexible irrigation scheduling to maximize crop yields. Results at field level were up-scaled to the entire command area of the system, showing the usefulness of soil water balance and of irrigation scheduling as analytical tools to demonstrate the inconsistency between the current water delivery and crops’ and farmers’ requirements. This preliminary work also allowed highlighting the need for modernizing the irrigation management in the first of the two study areas considered for the present research work (system 1 located in the province of Taranto, southern Italy).
An existing agro-hydrological model conceived to forecast water demand hydrographs in pressurized delivery networks was enhanced through several refinements and amendments of the computation algorithms. The refined model was applied for validation at different management levels on an existing pressurized irrigation system (system 2) located in the province of Foggia, southern Italy, where water withdrawals by farmers and the main hydraulic parameters are recorded on a continuous basis for monitoring purposes.
Results from validation showed that the model is capable of forecasting with good accuracy the timing of peak-demand periods, the seasonal demand irrigation volumes, as well as the hydrographs of hourly flow rates demanded by farmers during these peak periods, especially when it is applied to large multi-cropped command areas.
Performance indicators, originally conceived for diagnostic assessment in canal systems, were modified for application to pressurized distribution networks, and reference standard values were proposed. These indicators were then applied for validation to the second study area (irrigation system 2), where records of water deliveries are available, and showed their usefulness for diagnostic performance assessments.
Książki na temat "Rotational Irrigation Delivery System"
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Connellan, Geoff. Water Use Efficiency for Irrigated Turf and Landscape. CSIRO Publishing, 2013. http://dx.doi.org/10.1071/9780643106888.
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Achieving high water use efficiency in maintaining turf, trees and landscape areas is a core responsibility of open space managers. Water Use Efficiency for Irrigated Turf and Landscape provides a logical and scientifically sound approach to irrigation in urban areas in Australia. It is based on green space delivering defined outcomes using the principles of water sensitive urban design and irrigation efficiency.
The book covers all stages of the water pathway – from the source to delivery into the plant root zone. Major topics include system planning, estimating water demand, water quality, irrigation systems, soil management and irrigation performance evaluation.
Clearly presented explanations are included, as well as line drawings and worked examples, and a plant water use database covering more than 250 plant species. A Water Management Planning template is included to guide water managers and operators through a process that will deliver a sound plan to achieve sustainable turf, urban trees and landscapes.
Best Management Practice Irrigation principles are outlined and their implementation in open space turf and landscape situations is explained. The benefits and limitations of the various methods of delivering water to plants are covered, together with case studies and guidelines for specific horticultural situations. Methodologies to evaluate irrigated sites are included along with recommended benchmark values.
The book presents the latest irrigation technology, including developments in water application, control technology and environmental sensors such as weather stations, soil moisture sensors and rain sensors.
Części książek na temat "Rotational Irrigation Delivery System"
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Keller, Jack, i Ron D. Bliesner. "Main Delivery System Design". W Sprinkle and Trickle Irrigation, 201–20. Boston, MA: Springer US, 1990. http://dx.doi.org/10.1007/978-1-4757-1425-8_10.
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Zardari, Noorul Hassan, Sharif Shirazi, Irena Naubi i Siti Mariam Akilah Mohd Yusoff. "Is Farmer’s Agricultural Income Dependent on Type of Irrigation Delivery System?" W ISFRAM 2014, 161–69. Singapore: Springer Singapore, 2015. http://dx.doi.org/10.1007/978-981-287-365-1_14.
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Crouch, Dora P. "Planning Water Quality: Potable and Subpotable Water at Selinus and Priene". W Water Management in Ancient Greek Cities. Oxford University Press, 1993. http://dx.doi.org/10.1093/oso/9780195072808.003.0022.
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Today when the rigors of an arid climate (Arabia) or other constraints on water resources press the limits of water supply, hydraulic engineers have to reconsider the nineteenth century answer of one quality of water for all uses. In places where population density far exceeds the supply of potable water—Hong Kong—or where the scanty spring water is not enough to support the massive tourist industry—Bermuda—(Deb, 1987, 222) there is no choice but to use subpotable or nonpotable water whenever feasible. Absolute scarcity of drinking-quality water is the strongest reason for water managers today to consider alternate procedures, but in some situations the quality not quantity of water is the issue. Heavy metals, long-lasting pesticides, or other carcinogens may require separation of the purest supply for drinking and cooking from the less pure supply for other uses, lest the water itself cause disease during a lifetime of use. Since potable water amounts to a small fraction of use in a modern city—6 percent or less (J. Thapa, personal communication)—alternative delivery systems for that small amount may be feasible, with the main systems delivering subpotable water for bathing, cleaning, watering lawns, and so on, and nonpotable water for industry or irrigation. It is easier to contemplate in theory these logical divisions than to make actual plans for altering the delivery system in metropolitan water districts. Political and economic realities restrict change in built-up areas unless the danger is severe, but in some new suburbs in Florida dual pipelines are laid for potable water inside the house and subpotable outside. Drinking bottled water is becoming more common. Many municipal water systems now supply partially purified (nonpotable) water to industry for cooling or other processes. Still, these new ideas have not been widely implemented to date. It is unexpected, then, to find that the ancient Greeks had just such a triple system of water supply and reuse. Each Greek city had both public fountains and springs supplying flowing water of the best quality, and private cisterns in houses and public buildings to supply still water of good quality, plus a drain system that led used water outside the city.
Streszczenia konferencji na temat "Rotational Irrigation Delivery System"
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Sanger, Junaidy B., Heru Sukoco i Satyanto K. Saptomo. "Reliable data delivery mechanism on irrigation monitoring system". W 2014 International Conference on Advanced Computer Science and Information Systems (ICACSIS). IEEE, 2014. http://dx.doi.org/10.1109/icacsis.2014.7065878.
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Zhu, Xingye, Xinkun Wang i Junping Liu. "Numerical Simulation of a New Typed Sprinkler Irrigation System". W ASME-JSME-KSME 2011 Joint Fluids Engineering Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/ajk2011-24006.
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It has important significance and practical value for studying Sprinkler Irrigation System. In this study, numerical simulation was carried out. According to the selected materials and setting modes, both the pressure and the velocity distribution along the lateral were calculated out. Experimental study was carried out for this system to verify the correctness of numerical simulation. The following parameters were measured in the experiments: the flow-rate, rotational speed of the pump, and working pressure for the sprinklers. The numerical simulation results agreed to the experimental results within 5 percent. It supplied a foundation for the reasonable application of sprinkler irrigation system for the future. It can be concluded that structural optimization approach can be effectively implement by CFD simulation.
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Bharmal, Mohammad A., Syeda Q. Akbar, Sana Noor, Rabiya Farooq i Nauman A. Zaffar. "Hydrokinetic powered irrigation network automation: A scalable architecture for the enablement of real-time automated decentralized control of the irrigation water delivery system in developing countries". W 2017 IEEE Energy Conversion Congress and Exposition (ECCE). IEEE, 2017. http://dx.doi.org/10.1109/ecce.2017.8096812.
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Dakuri, Srinuvasu, i Bhaskar Roy. "Design of a Free Turbine for Simulation of Flow in a Turbine-Annular-Diffuser-With-Struts Delivery System". W ASME 2009 Power Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/power2009-81153.
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A free turbine is intended to produce the effect of a rotating flow field to be fed into a strutted annular diffuser for simulating a 3D fluid mechanic interaction and effect. This turbine is driven by the flow from a flow driver fan, upstream of the turbine. As sufficient pressure is required for the diffuser air flow, the concept of maximum work generation by a turbine is bypassed in the design intent. An inlet guide vane is designed for the turbine such that the rotational speed of the turbine matches the design intended speed and also produces an axial exit flow (no swirl) at design condition, and a rotating wake for off design conditions. The consideration of using of the inlet guide vanes (rather than usual stator-nozzles) is to avoid a mismatch between the absolute angle of the flow coming from the flow driver fan and the absolute design intent flow angle requirement, to run the turbine. Also, due to the 3D flow effects, some uncertainty exists in determining the exact entry air flow angle to the guide vane; this uncertainty is provided for with a rounded leading edge to the inlet guide vanes. The above design considerations when embedded in the conventional turbine design procedure resulted in an unusual turbine design with very low blade cambers.
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Lee, Joshua, Arun Prabhakar i Kathy Johnson. "Numerical Investigations Into the Oil Capture Efficiency of a Curve-Bladed Scoop System". W ASME Turbo Expo 2020: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/gt2020-15257.
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Abstract In civil aero-engines, the shafts are supported by oil-lubricated bearings. These bearings require sufficient lubrication to provide cooling and ensure the reliability of the engine. In some engine configurations, it is not possible to supply oil to the bearings via the traditional direct jet injection method. An oil scoop delivery system is one of the solutions proposed to solve this problem by directing oil from a nozzle towards a rotating plurality of scoops that have internal conduits to direct the captured oil to an under-race location. The performance of an oil scoop can be quantified by using its capture efficiency. The capture efficiency is defined as the ratio of oil delivered by the scoop system to the destination, to that supplied by the feed jet. In this numerical study, the performance of an oil scoop with a curved geometry was investigated in depth. This numerical study was carried out using the commercial computational fluid dynamics (CFD) code, ANSYS Fluent. The simulation adopted the Volume of Fluid (VOF) method for multiphase modelling and the model for turbulence modelling. The study investigated the effects of varying the rotational speed and jet angle on the capture efficiency of a curve-bladed oil scoop with a geometry closely resembling one taken from an existing patent. These findings were then compared with published results of a straight-bladed oil scoop for the same operating conditions and matched scoop tip radius. Both the curved and straight bladed oil scoops show similar trends in capture efficiency when rotational speed is increased. However, the capture efficiency of the curve-bladed oil scoop is higher than that of a straight-bladed oil scoop by 4% to 12% depending on the rotational speed. Comparison of the volume fraction contours shows that the amount of oil lost during the slicing event of the oil jet was lower using the curve bladed scoop as compared to the straight-bladed scoop. With regards to varying the jet angle it was observed that the capture efficiency of the curve-bladed scoop decreases as the jet becomes less tangential. However, it is found that more tangential oil jets can give lower capture efficiencies in straight bladed scoops. Results also indicated that the core flow pattern in the domain is affected by the blade geometry such that the capture efficiency is a function of the blade geometry. The vortex shedding characteristics for this specific geometry in single phase air were also investigated in depth in order to compare with published work on a straight bladed scoop. It was found that at the same rotational speed, the curve-bladed scoop has a slightly higher vortex shedding frequency than that of the investigated straight bladed scoop. Two different geometries which combined elements from the straight and curved blades were also assessed to determine their performance. It was found that both geometries had lower capture efficiencies than that of a fully curve-bladed scoop due to significant reduction in the oil momentum as it flows towards the outlet of the scoop leading to a higher proportion eventually being centrifuged out and lost from the scoop tip.
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Guerra, Davide, Marco Polastri, Mattia Battarra, Alessio Suman, Emiliano Mucchi i Michele Pinelli. "A Design Procedure for Multistage External Gear Pumps". W BATH/ASME 2020 Symposium on Fluid Power and Motion Control. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/fpmc2020-2797.
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Abstract In this work, the authors present a robust and integrated procedure for the design of multi-stage gear pumps to be used in dry sump system applications. Based on the target delivery flow rate, rotational speed and fluid properties, the developed iterative method enables to directly obtain the geometrical features and the working parameters of the pump components, such as gearpair specifics, shaft and journal bearing dimensions, clearance values. The methodology is then applied to a case study in order to highlight its features and detail the achievable outcomes. Quality of the results is assessed by means of a CFD analysis, demonstrating the capability to obtain the expected volumetric efficiency.
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Schroeder, Gunar, i Wieland Uffrecht. "A New Test Rig for Time-Resolved Pressure Measurements in Rotating Cavities With Pulsed Inflow". W ASME Turbo Expo 2010: Power for Land, Sea, and Air. ASMEDC, 2010. http://dx.doi.org/10.1115/gt2010-22596.
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The improvement of the overall performance and efficiency of gas turbines, especially in the internal cooling air system is of general interest. This requires the reduction of pressure losses induced by vortices and secondary flow. The steady state effects are known from literature and experiments. But also pressure fluctuations and oscillations e.g. resonances have an impact on the efficiency of the internal cooling air system. These unsteady effects are only principally discussed in the literature. Experimental investigations of pressure fluctuations and oscillations in rotating cavities, which are part of the internal air system, are very rare. One reason might be given by the fact that the investigation of these unsteady effects is a technical challenge especially for higher rotational speeds. This paper presents a new rotor test rig with a telemetric measurement system which permits time-resolved pressure measurements in the cavity. The cavity dimensions are similar to those of a real industrial gas turbine. The design of the test rig and the telemetric system allows rotational frequencies up to 10000 rpm. The current experimental investigation is focused on pressure fluctuations and oscillations in rotating cavities with through flow and their dependency on the test parameters. The aim is to find out the relevant effects for operation and design optimisation of rotating cavities in gas turbines. The rig consists of a stationary air delivery and an axial air transfer interface between the stator and the rotor. The rotor contains one cavity. The interface acts as a flow chopper. The air is blown from the stator drillings to the rotating inlet holes of the rotor which provide the connection to the cavity inside the rotor. The rotating holes pass the stator holes periodically, causing pressure fluctuations in the cavity. The frequency of the fluctuations depends on the rotational frequency of the rotor and the number of inlet and stator drillings, which can be varied. The tests are carried out for a range of the parameter Reφ, calculated with the outer radius of the cavity, up to 1·106 and for different mass flow rates. The new test rig, the setup, the instrumentation and the first measurements are the topic of this paper. The non-stationary effects found in the cavity and their dependency on the parameters rotational frequency and mass flow will be discussed and compared with known theoretical approaches.
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Boughner, Kyle J., John E. Wentz i Benton J. Garske. "Development and Validation of a Mathematical Model of Microfilm Formation in Atomization Cooling of Micromachining". W ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-65302.
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Traditional flood cooling processes can cause problems in micromachining due to the collision force between the fluid stream and the tool being greater in magnitude than the cutting forces. The traditional processes produce insufficient cooling rates and are unable to effectively evacuate chips from the cutting zone. Atomization-based cooling addresses these issues through high evaporative cooling rates, low impact forces, and the use of a high velocity air stream to clear the cutting zone of chips. This paper presents a probabilistic model to determine the thickness of a microfilm forming on a rotating cylindrical surface, such as a microturning workpiece or a microendmill, and the relative importance of system parameters on film formation. The rate of microfilm formation is dependent upon droplet losses in the tube, at the nozzle, and the scatter of the atomized spray. Droplet diameters and Weber numbers in the tube and at the cylinder were experimentally determined and modeled as lognormally distributed. Parameters investigated in this model are fluid and mist properties (surface tension and droplet size) and system parameters (delivery tube air velocity, spray air velocity, spray geometry, cylinder diameter, and cylinder rotational velocity). A maximum film thickness effect was found for the variables of delivery tube velocity, droplet diameter, and surface tension with a value for each variable that provided a thickest film. As the variables increased or decreased from that value the film thickness decreased.
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Shamekhi, Amir H., i Ali Gaffari. "An Improved Model for SI Engines". W ASME 2004 Internal Combustion Engine Division Fall Technical Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/icef2004-0818.
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In this paper an improved mathematical model of spark ignition engines is presented. The model is derived based on a combination of thermodynamically relations and dynamical characteristics of engines. The geometrical parameters of the engine, valves and spark timing, air to fuel ratio, specific fuel consumption and engine operational conditions are considered during all four strokes of the engines. The engine is divided into some related subsystems namely; throttle body, intake manifold, fuel delivery system, intake and exhaust valves, E.G.R., torque production system, rotational dynamics and emission system. Each subsystem is modeled and the inter-relation between them has been considered. A new computer code is developed in Visual C++6 based on derived relations. This code may be considered as an appropriate means to investigate the performance of a given SI engine and to derive the emission results. The computer code is able to evaluate twelve combustion production species in a full thermodynamic equilibrium. Other engine performance quantities such as power, torque, thermal efficiency, work done by piston, pressure and temperature time histories are also evaluated in this simulation.
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Javiya, Umesh, John Chew, Nick Hills i Timothy Scanlon. "A Comparative Study of Cascade Vanes and Drilled Nozzle Designs for Pre-Swirl". W ASME 2011 Turbo Expo: Turbine Technical Conference and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/gt2011-46006.
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Design of pre-swirl systems is important for the secondary air cooling system of gas turbine engines. In this paper, three pre-swirl nozzles, a cascade vane and two drilled nozzles are analysed and their performances are compared. The two drilled nozzles considered are a straight drilled nozzle and an aerodynamically designed nozzle. CFD analyses are presented for stand-alone and pre-swirl system 3D sector models at engine operating conditions near to engine maximum power condition rotational Reynolds number (Reφ) up to 4.6 ! 107. Nozzle performance is characterised by the nozzle discharge coefficient (CD), nozzle velocity coefficient (η) and cooling air delivery temperature. Two commonly used eddy viscosity models are employed for the study, the standard k-ε and Spalart-Allmaras models with wall functions. Both models give very similar results for CD and η, and are in reasonable agreement with available experimental data. Effects of nozzle or vane number and sealing flow have been analysed. The cascade vanes perform slightly better than the aerodynamically designed drilled nozzles but the final design choice will depend on other component and manufacturing costs. An elementary model is presented to separate temperature losses due to the nozzle, stator drag and sealing flow.