Small Water Flow Research Articles

HYDROELECTRIC PLANTS AN IMPORTANT FACTOR FOR ENERGY SECURITY / ՀԻԴՐՈԷԼԵԿՏՐԱԿԱՅԱՆՆԵՐԸ ԷՆԵՐԳԵՏԻԿ ԱՆՎՏԱՆԳՈՒԹՅԱՆ ԿԱՐԵՎՈՐ ԳՈՐԾՈՆ

Currently, a large amount of work is being done for the development of hydropower in Armenia. However, there is still a lot to be done to build new powerful plants and modernize the old ones. At the moment the Sevan-Hrazdan, Vorotan cascades and other HPPs are being operated, which provide a third of Armenia's electricity. From the point of view, it is also important to put the energy use of small water flows on the agenda. It is planned to build the Meghri and Shnogh HPPs, which will make it possible to improve the situation to some extent. The design and operation of hydroelectric power plants is of great importance for the development of Armenia's energy. It will provide an opportunity to improve the energy security of our country. The purpose of the work is to substantiate the need to build a hydroelectric power station on the Chknagh River near the city of Stepanavan in Lori Marz, RA. Methodology. The basic equations of hydraulics, as well as the basic laws of HPP design, were used in the research. Scientific novelty. It is justified that if we build a hydroelectric power station on Chknagh river, we can save 3460 tons of organic fuel per year and solve many environmental problems. Applicability. The proposal can be applied in the Lori region of the Republic of Armenia. It has been established that in case of building a hydroelectric power plant on the Chknagh River, we can save 3460 tons of organic fuel per year and improve the climatic conditions. We can produce 17.13 million kWh of electricity annually. The purchase period with investments is 10.4 years.

Confluence simulations based on dynamic channel parameters in the grasslands lacking historical measurements

Technology has greatly promoted ecohydrological model development, but runoff generation and confluence simulations have fallen behind in ecohydrological model development due to limited innovations. To fully understand ecohydrological processes and accurately describe the coupling between ecological and hydrological processes, a distributed ecohydrological model was constructed by integrating multisource information into distributed dynamic process model (DDPM). We mainly describe runoff generation and convergence modules. Based on the improved HBV model and degree-3 h factor method, runoff generation and snow routines were constructed for semiarid grassland basins. In view of meandering and variable steppe river channels and steep hydrological relief characteristics, a confluence module was constructed; the 1-km bend radius equivalent concept was innovatively proposed to unify river channel bend degrees. The daily runoff simulation validation results obtained using two datasets were R2 = 0.947 and 0.932, NSE = 0.945 and 0.905, KGE = 0.971 and 0.680. In the 3-hour flood simulations, the DDPM could better restore small long-distance water flows than the confluence method that did not consider actual river lengths or bend energy losses; the DDPM more accurately simulated the flood peak arrival time than the confluence method that did not consider overflow. The simulated mainstream overflow frequency increased by 0.84/10 years, and significant interaction periods of 10 to 13 years occurred with local precipitation, ecological status, and global climate change. An approximately 2-year lag occurred in the global climate change response. This study helps us further understand and reveal the ecohydrological processes of steppe rivers in semiarid regions.

Occurrence and mass loads of N-nitrosamines discharged from different anthropogenic activities in Desheng River, South China

N-nitrosamines are widespread in various bodies of water, which is of great concern due to their carcinogenic risks and harmful mutagenic effects. Livestock rearing, domestic, agricultural, and industrial wastewaters are the main sources of N-nitrosamines in environmental water. However, information on the amount of N-nitrosamines these different wastewaters contribute to environmental water is scarce. Here, we investigated eight N-nitrosamines and assessed their mass loadings in the Desheng River to quantify the contributions discharged from different anthropogenic activities. N-nitrosodimethylamine (NDMA) (< 1.6-18ng/L), N-nitrosomethylethylamine (NMEA) (< 2.2ng/L), N-nitrosodiethylamine (NDEA) (< 1.7-2.4ng/L), N-nitrosopyrrolidine (NPYR) (< 1.8-18ng/L), N-nitrosomorpholine (NMOR) (< 2.0-3.5ng/L), N-nitrosopiperidine (NPIP) (< 2.2-2.5ng/L), and N-nitrosodi-n-butylamine (NDBA) (< 3.3-16ng/L) were detected. NDMA and NDBA were the dominant compounds contributing 89% and 92% to the total N-nitrosamine concentrations. The mean cumulative concentrations of N-nitrosamines in the livestock rearing area (26 ± 11ng/L) and industrial area (24 ± 4.8ng/L) were higher than those in the residential area (16 ± 6.3ng/L) and farmland area (15 ± 5.1ng/L). The mean concentration of N-nitrosamines in the tributaries (22ng/L) was slightly higher than that in the mainstem (17ng/L), probably due to the dilution effect of the mainstem. However, the mass loading assessment based on the river's flow and water concentrations suggested the negligible mass emission of N-nitrosamines into the mainstem from tributaries, which could be due to the small water flow of tributaries. The average mass loads of N-nitrosamines discharged into the mainstem were ranked as the livestock rearing area (742.7g/d), industrial area (558.6g/d), farmland area (93.9g/d), and residential areas (83.2g/d). In the livestock rearing, residential, and industrial area, NDMA (60.9%, 53.6%, and 46.7%) and NDBA (34.6%, 33.3%, and 44.9%) contributed the most mass loads; NDMA (23.4%), NDEA (15.8%), NPYR (10.1%), NPIP (12.8%), and NDBA (37.8%) contributed almost all the mass loads in the farmland area. Photodegradation amounts of NDMA (0.65 ~ 5.25µg/(m3·day)), NDBA (0.37 ~ 0.91µg/(m3·day)), and NDEA (0 ~ 0.66µg/(m3·day)) were also calculated according to the mass loading. Quantifying the contribution of different anthropogenic activities to the river will provide important information for regional river water quality protection. Risk quotient (RQ) values showed the negligible ecological risks for fish, daphnid, and green algae.

Prospects of Mapping Alternative Energy Resources Based on Foreign Experiences

This article is based on foreign experiences of mapping alternative energy sources, developing a regional and local level database and maps on the use of alternative energy resources, collecting statistical data on wind, solar, small water flows, geothermal resources, natural and Schematization of socio-economic indicators is dedicated to the analysis of the results of scientists who are conducting certain scientific research works on the use of alternative energy resources in our country today.

Performance improvement of air-source heat pump heating system with variable water temperature difference

Heating electrification is a trend for the current carbon neutrality setting. The air-source heat pump (ASHP) has been widely used in residential or commercial buildings to replace household coal-burning stoves due to its higher operating efficiency. Previous studies mainly focused on the heat pump equipment, ignoring the whole system performance in practical application. Among the auxiliary system of the ASHP heating system, the power consumption of water pump cannot be ignored, especially in residential district heating with a large amount of pipeline. This paper proposes the coefficient of performance (COP) improvement of the ASHP heating system through variable temperature difference and flow rate of circulation water loop, showing the feasibility and benefit of large temperature difference with small flow rate. A high-fidelity dynamical model is first built using Dymola, followed by the experiments verification at the environmental laboratory. On all testing conditions, the system COP of large temperature difference with small water flow rate shows average 6% to 8% improvement compared to small temperature difference with large water flow rate. Further, a demonstration heating project of the ASHP system was tested onsite under a realistic operating condition. The recorded hourly operation data showed an average system COP of 2.15 at the condition of large temperature difference, which is about a 7% improvement compared to the small temperature difference condition for the typical heating day.

Experimental and Simulative Investigations on a Water Immersion Cooling System for Cylindrical Battery Cells

High charge/discharge rates and high energy density require a greater cooling power and a more compact structure for battery thermal management systems. The Immersion cooling (direct liquid cooling) system reduces the thermal resistance between the cooling medium and the battery and greatly enhances the cooling effect of the system. However, the high viscosity and low specific heat capacity of dielectric fluid limit the cooling effect of immersion cooling. This study presents an immersion cooling system that uses water as the cooling medium. In this system, a special seal structure was designed to prevent contact between water and the battery’s electrodes. The cooling effect of the system on the battery pack was numerically studied. Even if the battery pack is discharged at 3 C rate, a small water flow rate (200 ml/min) can ensure that the maximum temperature of the battery pack falls below 50°C. However, a good cooling capacity will increase the temperature difference of the battery pack. The temperature difference of the battery pack is difficult to reduce to 5°C until the water flow rate exceeds 1,000 ml/min. Adding a buffer structure at the inlet/outlet can be reduced the negative effects of the turbulent flow and then improve the temperature uniformity of the battery pack. These findings provide a better understanding of the influencing factors of the water immersion cooling system and can help to design a better immersion cooling system.

On the desalination performance of multi-layer graphene membranes; A molecular dynamics study

In this study, the efficiency of a multi-layer graphene membrane with fully aligned pores was discussed in the desalination process. By changing the configurations and parameters such as pore size, pressure, thickness, ion concentration, and pore geometry, the water transfer rate has been observed from the scale 100 to 1000 L/m2 h bar, which is very close to the transfer rate of water through single-layer graphene sheet and three times larger than conventional reverse osmosis membranes. Small pores (with 0.6 nm in diameter) in the multi-layered graphene membrane pass a small water flow rate even when the high pressures. More water flow rate could be achieved in larger pores, but in the pores with diameters larger than 1.2 nm, the salt rejection is weakened. Increasing the number of layers from five to ten can completely cease the water flow in the same pore diameter. With a 40% reduction in the concentration of ions in the feed area, the water transfer rate is increased by about half. The results of this study can be useful for making a superior membrane for future water crises.

Effects of water flow rate and surface cover plant density on the growth of duckweed (Lemna minor L.)

Globally, agriculture sector is facing unprecedented challenges in producing fertilizers and increasing the amount of fertilizer production without having negative impact on the environment. Thus, the organic fertilizers are needed to be produced as they do not give any damages to the environment. Duckweed plant has a lot of potentials that can be used in the agriculture sector. This plant can breed in approximately 16-48 hours by splitting. The water needs and its breeding speed ability are the basis for conducting this research. The research objective was to determine the effect of water flow rate and surface cover plant density on the growth and yield of duckweed plants. This research was conducted in November–December 2018 in Cangkringan District, Sleman, Special Region of Yogyakarta, Indonesia. The experiment was arranged in a split plot design. The main plot was irrigation water flow rate, consisting of two levels, namely large water flow rate (0.336 L.second-1) and small water flow rate (0.085 L.second-1). The subplot was the density of the duckweed plant surface cover, consisting of 10%, 20%, 40% and 60%. The results of this study indicated there was no effect of water flow rate on the plant growth, yield, and yield quality of duckweed plants. The C/N ratio of the duckweed plants fulfilled the requirement to be used as green manure.

Gravitational water vortex pico hydro power modeling for aquaculture implementation

Nanotechnology and Graphene Research Centre (PRINT-G) of Universitas Padjadjaran is currently developing fine bubble generator (FBG) technology which is applied for the fisheries sector to process aquaculture wastewater into clean water and as an aerator. In its implementation, adequate energy is needed, but it can be applied with cheaper electricity costs, such as renewable energy sources. In this research, a gravitational water vortex pico hydro power (GWVPHP) plant modeling has been carried out. .This system can be used under 2 meters head condition and for small water flow, that is suitable to use in fishing pond locations that do not have high head and limited water. It is known that the velocity of water flow is 0.4 m/s, and the head is 1.6 meters with the height level of the water varying every 5 centimeters increase in the range of 5 to 50 centimeters. As a result, we obtained the minimum potential power of 111.9 Watt and a maximum of 1,558.2 Watt. In modeling, we assumed that we used turbine with 80 percent efficiency, thus we obtained the turbine generation power of 89.6 Watt, and a maximum of 1,246.6 Watt. In addition, the modeling also uses 3 phase AC generators with an efficiency value of 70 percent, so that a minimum generator generation power of 62.7 Watt is obtained, and a maximum of 872.6 Watt is obtained. Control panel also used with an efficiency of 70 percent, so that a minimum power that produced is 43.9 Watt, and a maximum of 610.8 Watt. Fine bubble generator (FBG) that used for aquaculture needs 125 Watt to be functioned. Thus, the power that had generated by the gravitational water vortex pico hydro power (GWVPHP) plant could be supplied the energy needs of fine bubble generator (FBG).

Erosion characteristics of loess tunnels on the Loess Plateau: A field investigation and experimental study

AbstractLoess tunnels are a common geo‐hazard in the Loess Plateau and not only cause considerable soil and water loss, but also aggravate and even induce the occurrence and development of other disasters such as ground fissures, mudflows, collapses, and landslides. To date, research on the hydrological characteristics and erosion behaviour of loess tunnel systems has focused on field investigation data and limited river basin observation data, whereas field test information and data are very scarce. In this study, field surveys, observations, field scouring experiments, and laboratory‐based sediment percentage tests were conducted to analyse the erosion characteristics, spatial distribution, and hydrological characteristics of a large‐scale loess tunnel system in the hilly Loess Plateau southeast region of northern China. The results showed that the loess tunnel erosion exhibited periodicity. Tunnel erosion in each period shows a similar erosion process, that is, thin‐layer water flow erosion and lateral expansion, tunnel wall collapse and deposit due to the loss of support from the lateral erosion, and erosion and transport of deposits by water flow. Waterfall erosion, lateral erosion, headward erosion, and the resulting collapses were the main forms of tunnel erosion. Besides this, the base level of erosion significantly affects the erosion characteristics of the loess tunnel. The hydrological characteristics during field scouring experiments exhibited three different stages: a lag effect, attributed to the temporary loss of water velocity in the first stage; small water flow fluctuations in the second stage; and an increase in total seepage loss with increased water injection flow in the third stage. The erosion rate was positively correlated with the flow quantity. The results of this study not only provide valuable reference data for research on the mechanism and velocity of erosion events in loess, but also provide a theoretical basis for the prevention of loess tunnel disasters in engineering construction. © 2020 John Wiley &amp; Sons, Ltd.

Design, Fabrication and Performance Test of Axial Flow Hydro Turbine

Hydropower is the source of renewable energy for more than a century leading to a decrease in the burning of fossil fuels whichhas an effect on the environment. The axial flow hydro turbine is placed for a small water flow rate and the low head application. Axial flow hydro turbine consists of guide vane mounted in the stationary casing and blades connected on the hub. Axial flowhydro turbine consists of four runner blades, the number of guide vane is 6 and the guide vane angle is 73˚. In this research, theavailable head and flow rate are 3.4 m and 0.14 m3/sec. Hydrofoil shape of runner blade selected NACA 6412 and modeling theblade geometry used SolidWorks software. In this research, the modal of the axial flow hydro turbine is made with thermoplasticfilament material due to produce easily. The turbine assembly was tested with various water velocities at Lon Town IrrigationChannel in Madayar Township, Myanmar. Experimental results of turbine shaft power and generator output power are alsoestimated in this research. The maximum turbine shaft power and generator output power are observed 3.66 kW and 3 kW atvolume flow rate of 0.15 m3/s.

The environmental and landscape values of the small lowland river valley and their threats on the example of the Kraska river (Masovian Voivodeship)

The environmental and landscape values of the Kraska River Valley as the typical example of small lowland water flow path were analysed. The WULS-SGGW method, allowing to the estimation of whole valley reach as well as its peculiar eco-morphological zones, was used. The unregulated, regulated in the years 1990– –2012 and continuously maintained from the year 2015 reaches are present in the valley. It was stated that the unregulated reaches characterise themselves by higher environmental values and biological diversity, especially in the case of invertebrate fauna. The invertebrates, as the key element of the river community, quickly rebuild their structure after the termination of maintenance works. The vertebrate fauna, even unconnected strictly with the riverbed, shows higher values on the unmaintained valley reaches.

The Development of Small Water Flow Facility at National Institute of Metrology, Thailand

The flow and volume of liquid laboratory of the National Institute of Metrology, Thailand (NIMT) has developed the latest facility which covers the liquid flow measurement ranges from (10 – 1,000) g/h. This facility has been developed according to the need of high accuracy equipment in several industries such as pharmaceutical products, fuel cells, semiconductor and medical devices. For accuracy purposes, the gravimetric method is decisively implemented as the main principle of the calibration rig. It comprises of three main parts; water supply system, weighing system and data acquisition system. Practically, the capability of the facility is confirmed via a transfer standard. With high accuracy and repeatability, the Coriolis mass flow controllers were selected as the transfer standard. The facility can provide the best capability of calibration, CMC, at 0.30% of reading. Moreover, the evidence of unofficial comparison between NIMT and Federal Institute of Metrology, METAS, Switzerland, has confirmed this capability via the degree of equivalence, En ratio. The En ratios represent that the comparison of the flow rates from (10 – 1,000) g/h between NIMT and METAS is agreed.

Release of hydrogen sulfide in a sewer system under intermittent flow conditions: the Eiceira case study, in Portugal.

The presence and fate of hydrogen sulfide in wastewater systems were studied in two stretches of an intercepting sewer system located in a coastal village, in Portugal. A range of hydraulic parameters were obtained and liquid and gas phase measurements were carried out, both continuously and through intensive sampling campaigns. Upstream, where flow rates were relatively low, dissolved sulfide concentrations around 12 mg S L-1 and hydrogen sulfide gas concentrations above 250 ppm were observed, along with limited corrosion damage. It is believed this is due to the low relative humidity detected along the atmosphere of the studied sewer system. Downstream, gas concentrations were always below 40 ppm. Despite that, high signs of corrosion were detected, particularly in manholes with drop structures. It is thought that condensation of spray produced by the fall is the main cause of the phenomenon. Another relevant observation was the rapid decline in dissolved sulfide contents along gravity trunk sewers following the discharge of rising mains, with loss rates as high as 40 mg S L-1 h-1. Air-flow velocities corresponded to 15-50% of wastewater flows, an observation which agrees with other authors' publications addressing relatively small pipes and moderate water flows.

Design and Computational Fluid Dynamic Simulation Study of High Efficiency Cross Flow Hydro-power Turbine

Cross-flow hydraulic turbine becomes viable in low head and small water flow rate. Because of its simple in structure and ease of manufacturing, it is familiar in scheme of small hydro-power in the site of the power plant. In order to obtain a cross-flow turbine with maximum efficiency, appropriate turbine design must be performed. Therefore here proper turbine design was done employing the all turbine parameters and computational fluid dynamic simulation was carried out as important tool for performance study of the turbine. The required turbine model was designed and computational fluid dynamics simulations was performed by using the commercial software ANSYS CFX v.12. After the high efficiency turbine was designed, computational fluid dynamics was conducted in order to validate the obtained solution. With attack angle of 180, maximum efficiency was found to be 82.52% constant for different values of head and water flow rate. Where as in CFD simulation case, maximum efficiency became 79% with fully opened guide vane. Guide vane was set at position where the water is discharge through the runner fully. In this paper all design parameters of cross-flow turbine were calculated at maximum efficiency and simulation was done by opening turbine gate value at different stages.

Anti-freezing water flow rates of various sectors for natural draft dry cooling system under wind conditions

Freezing risk of air-cooled heat exchangers for natural draft dry cooling system is a key concern in power plants during cold days, so it is beneficial to the safe and economic operation of natural draft dry cooling system to propose the anti-freezing measures at various ambient conditions. As a main issue, the anti-freezing water flow rate of air-cooled heat exchanger is investigated by using the macro heat exchanger model based on the heat load balance between the circulating water and ambient air. The detailed thermo-flow characteristics of the cooling deltas and the anti-freezing water flow rate for each sector at various wind speeds are obtained with reference to the water freezing temperature, and the residual anti-freezing coefficient is introduced to describe the affluent anti-freezing capacities of each sector and cooling delta at the anti-freezing water flow rate. The results show that the anti-freezing water flow rate is highest and the residual anti-freezing coefficient is lowest for the frontal sector compared with those for other sectors. For the middle and middle-rear sectors, even with small anti-freezing water flow rates, the residual anti-freezing coefficients can be high because of the reduced heat rejection to the deteriorated air flows.

Inter-laboratory comparison of small water flow calibration facilities with extremely low uncertainty

Abstract In this paper, the results of an inter-laboratory comparison of two small water flow calibration facilities with extremely low uncertainty between Endress+Hauser Japan Co. Ltd. (E+H-J) and the National Metrology Institute of Japan (NMIJ) is reported. Flowrate range between 30 kg/h and 36,000 kg/h is compared. Expanded uncertainty of mass flowrate is from 0.020% to 0.025% at E+H-J and from 0.021% to 0.023% at NMIJ. In order to achieve low uncertainty, NMIJ carries out a re-evaluation of the uncertainty budget for two weighing tank systems. With advanced control of ambient temperature and calibration, the uncertainty level can be reduced to approximately half of previous levels. Results of the inter-laboratory comparison show excellent agreement for both standards, which is less than 0.018%. En values are also less than 0.52 for all examined flowrate points. These results show a high level of consistency for the facilities at both labs. To know the substantial difference, comparison is performed using corrected fitting curves between the flowrate by the test meters and the reference. As a result, significant difference between two facilities was quite small, and is estimated to be less than 0.001%. Differences in this comparison are one or two orders of magnitude lower than previous comparisons on water flow.

Effects of experimental snowmelt and rain on dispersal of six plant species

AbstractWater flows affect dispersal of propagules of many plant species, and rivers and streams are therefore very important dispersal vectors. However, small water flows such as trough rain and snowmelt are much more common, but their effects on dispersal are barely studied. The importance of this form of dispersal deserves attention, especially when considering that climate change is predicted to change the amounts of rain and snow worldwide. Dispersal through melting snow and rain was addressed experimentally, using artificial soils mounted on slopes with different angles and subjected to a melting snow pack or an equivalent amount of dripping water. Seeds on the soil moved on average 3·02 cm (±1·81 SE) in rain treatments and 0·23 cm (±0·3 SE) in snowmelt treatments. Tracking plastic granules in field conditions further showed that snowmelt exhibited minimal dispersal capacity. Dispersal distances by rain were enhanced by increasing slope angles and with decreasing seed volume. Given that many species in cold environments have small seeds, dispersal by rain could provide an important (secondary) dispersal mechanism in these habitats. © 2016 The Authors. Ecohydrology published by John Wiley &amp; Sons Ltd.

The Simud–Tiu Valles hydrologic system: A multidisciplinary study of a possible site for future Mars on-site exploration

When looking for traces of past life on Mars, we have to look primarily for places where water was present, possibly for long time intervals. The Simud and Tiu Valles are two large outflow channels connected to the north with the Chryse Basin, Oxia Palus quadrangle. The area, carved by water during the Noachian/Early Hesperian is characterized by a complex geological evolution. The geomorphological analysis shows the presence of fluvial and alluvial structures, interpreted as fluvial channels and terraces, debris flow fronts and short-lasting small water flows coexisting with maar-diatremes and mud volcanoes. Several morphological features indicate a change in water flux direction after the main erosive phase. During this period water originated from the Masursky crater and flown southwards into the Hydraotes Chaos. This phenomenon caused the studied area to become a depocenter where fine-grained material deposition took place, possibly in association with ponding water. This setting is potentially quite valuable as traces of life may have been preserved. The presence of water at various times over a period of about 1Ga in the area is corroborated by mineralogical analyses of different areas that indicate the possible presence of hydrated minerals mixtures, such as sulfate-bearing deposits. Given the uniqueness of the evolution of this region, the long term interactions between fluvial, volcanic, and tectonic processes and its extremely favorable landing parameters (elevation, slope, roughness, rock distribution, thermal inertia, albedo, etc.), we decided to propose this location as a possible landing site for the ESA ExoMars 2018, the NASA Mars 2020 and future on-site missions.

Funcionalidad actual de la "Fuente la Mina". Lorca (Región de Murcia)

La galería de la fuente La Mina, en La Paca, Lorca, es un ejemplo de galería con lumbreras en la Región de Murcia. A pesar de la sequía actual en este territorio (2013-2014), este sistema tradicional de aguas continúa alumbrando un pequeño caudal, motivo por el que la cercana comunidad de regantes Campo Alto ha realizado una solicitud a Confederación Hidrográfica del Segura para disponer de estos recursos y mantener su espacio regado.