Hydraulic Performance Assessment Research Articles

Hydraulic performance assessment on dynamic fluidic and complete fluidic sprinklers under indoor and outdoor conditions

Since Complete Fluidic Sprinklers (CFS) cannot function well in low-pressure environments, Dynamic Fluidic Sprinkler (DFS) were developed to address this issue. In 2021, research in the field and laboratory were conducted to examine how well DFS and CFS performed hydraulically in both indoor and outdoor conditions. In this investigation, a Thiess Clima laser precipitation monitor was used to evaluate the droplet size and velocity distribution of two different types of sprinklers indoors. From the findings, DFS velocities ranged from 0.1 to 4 m/s whereas CFS ranged from 0.1 to 5.3 m/s. The maximum frequency value was obtained at velocities of 1 m/s for each combination. The DFS had a slightly greater discharge coefficient and spray pattern than the CFS. The DFS's maximum spray range was 12.2 m, while the CFS's maximum spray range was 10.8 m, with standard deviations of 1.07 and 1.66, respectively. Under high wind speed conditions, the maximum combined Coefficient of Uniformity (CU) of DFS and CFS were 81.1% and 78%, respectively. For a given pressure and sprinkler spacing, DFS delivered higher CU values than CFS, especially while running at low pressure, demonstrating that DFS offered a more favoured water distribution pattern at low pressure. At different distances from the sprinkler, the highest application rates for DFS and CFS were 6.7 mm h−1 at 7 m and 6.5 mm h−1 at 7 m, respectively. A comparison of DFS and CFS under hydraulic performance indicated that DFS had a better performance than CFS. The study can serve as a guide for how to conserve water in sprinkler-irrigated fields.

Hydraulic performance assessment of various submerged pile designs around an emerged dike

This study aimed to devise strategies for alleviating the detrimental impacts of floods in the vicinity of a dike. Experiments were conducted in an open rectangular channel to investigate the flow dynamics under varying dike conditions. To address concerns related to intense whirls and concentrated flow around the dike head, comparative analysis was performed in terms of flow structures and energy reduction around I-shaped and T-shaped dikes with two ratios of wing length (lw) to dike length (ld) (lw/ld = 1.41 and 2.43). The T-shaped dike wings were equipped with diverse designs: angled footing, delta vane, and streamlined tapered, resulting in elevated backwater in front of the dike, reduced velocity, and enhanced energy reduction. The findings indicated that elongating the wing reciprocally affected the depth-averaged velocity (at the dike head and near the adjacent dike bank), concurrently impacting flow deflection, backwater rise, and energy reduction rate. The T-shaped dike, specifically with an angled footing (lw/ld = 2.43), yielded optimal outcomes. These included significant reductions in maximum energy (46%), tip velocity (98%), and dike adjacent bank velocity (90%), as well as significant flow deflection towards the mainstream, outperforming the I-shaped impermeable dike. The proposed solutions exhibit efficacy in mitigating rapid deterioration during floods, securing both the dike head and the neighboring bank to avert failures in high-energy flow.

Hydraulic performance assessment of a multi-layered landfill cover system under constant water ponding

Abstract The engineered multi-layered cover system (MLCS) is used to minimize rainwater infiltration into the wastes accommodated in near surface waste disposal facility (NSDF). It is important to assess the hydraulic performance of MLCS before deploying it in the field. For this purpose, an instrumented three-layered soil column representing MLCS was subjected to 1.5 m constant ponding head for 400 days. The variation of volumetric water content and soil water potential was monitored as a function of depth and time. The objective of the study is to understand the long-term hydraulic performance and rate of saturation of different layers of MLCS. Under constant water ponding, the time to saturation for 0.3 m in surface layer, 0.6 m in drainage layer and 1.0 m in hydraulic barrier layer was observed as 24, 223 and 262 days, respectively. The numerical analysis of the MLCS predicted comparable time duration of 25, 234 and 272 days, respectively. It was noted that the numerical simulation performed by using measured wetting hydraulic parameters matched well with the experimental observation. The importance of soil specific calibration of water content sensors to improve the accuracy of observations was demonstrated. Percentage error in the estimation of layer specific soil water storage, clearly indicates that the volumetric water content measurements using profile probe was marginally better than 5TM measurements.

A Comprehensive Compendium on Passive Augmentation Techniques for Enhancement of Single-Phase Heat Transfer Coefficients in Heat Exchanger Tubes under Laminar and Turbulent Flow Conditions

Several passive techniques can substantially improve the heat transfer performance of conventional heat exchangers. Passive methods persistently use heat transfer augmentation inside tubular sections, which tackle dominant thermal resistance. The thermal resistance in turbulent flow is primarily due to a thin viscous sublayer near the tube wall. This proliferates into the cross-section of the conduit in the case of laminar flows due to the existence of a relatively thicker boundary layer. This urges disturbance in the entire fluid throughout the cross-section in laminar flows, whereas augmentation devices are usually located close to the wall for turbulent flows. Most of these methods yield increased fluid residence time within the system by inducing swirling motion. The form of disturbance in the flow field is the characteristic of the passive technique used to prolong the fluid residence time and is exhibited differently in both flow regimes. The present article showcases a comprehensive review of heat transfer enhancement through thermo hydraulic performance assessment of these methods reported in the literature. The comparison is based on ratios of Nusselt numbers, first at the same Reynolds numbers, and then, at equal pumping power with constant heat transfer area.

Assessment of hydraulic performance and fouling control caused by pulse flow in hollow fiber membrane module

AbstractTo shed light on the effect of pulse flow on shear force and membrane fouling, the pulse frequency and flow velocity based on fiber Bragg grating (FBG) sensing technology were studied. The results show that there is a threshold for this synergy between the pulse frequency and flow velocity, which forms more easily at a high pulse frequency and low flow velocity. Moreover, the transition from pulse flow to continuous flow affects the shear force distribution with the membrane module height. Besides, at the same volumetric flow, Re gradually reaches a plateau as the pulse frequency increases from 1 to 5 Hz, and the membrane fouling control has a better flux recovery, which can reach a maximum of 28.89%. Finally, the results also show that the combined effect of high pulse frequency and low flow velocity would be higher than that of low pulse frequency and high flow velocity.

A Simplified Sanitary Sewer System Generator for Exploratory Modelling at City-Scale

Future climatic, demographic, technological, urban and socio-economic challenges call for more flexible and sustainable wastewater infrastructure systems. Exploratory modelling can help to investigate the consequences of these developments on the infrastructure. In order to explore large numbers of adaptation strategies, we need to re-balance the degree of realism of sewer network and ability to reflect key performance characteristics against the model's parsimony and computational efficiency. We present a spatially explicit algorithm for creating sanitary sewer networks that realistically represent key characteristics of a real system. Basic topographic, demographic and urban characteristics are abstracted into a squared grid of ‘Blocks’ which are the foundation for the sewer network's topology delineation. We compare three different pipe dimensioning approaches and found a good balance between detail and computational efficiency. With a basic hydraulic performance assessment, we demonstrate that we attain a computationally efficient and high-fidelity wastewater sewer network with adequate hydraulic performance. A spatial resolution of 250 m Block size in combination with a sequential Pipe-by-Pipe (PBP) design algorithm provides a sound trade-off between computational time and fidelity of relevant structural and hydraulic properties for exploratory modelling. We can generate a simplified sewer network (both topology and hydraulic design) in 18 s using PBP, versus 36 min using a highly detailed model or 1 s using a highly abstract model. Moreover, this simplification can cut up to 1/10th to 1/50th the computational time for the hydraulic simulations depending on the routing method implemented. We anticipate our model to be a starting point for sophisticated exploratory modelling into possible infrastructure adaptation measures of topological and loading changes of sewer systems for long-term planning.

Spillway hydraulic performance assessments of the Belogorsk reservoir

The article presents the calculation of the hydraulic performance of the spillway structure of the Belogorsk reservoir, one of the largest freshwater bodies on the Crimean Peninsula. Due to its geographical location and natural features, Crimea has always been and remains one of the poorest regions of Russia with water resources and water delivery to the consumers is a priority. Hydraulic performance assessment of the spillway structure is carried out for two design cases: 1) with a variable upstream water level rate and a fully open gate with a = 1.00 m; 2) with a constant upstream water level (UWL) equals highest water level (HWL) and a variable value of the shutter opening. Based on the results of determining the hydraulic performance of the water intake structure, the maximum discharge flow rate (at the mark UWL equals HWL) was obtained, which was Q = 6.06 m3 / s, which is 1% higher than the design data of the throughput of the structure (Q = 6.00 m3 / s) and the total throughput of all spillway structures is Qtotal = 79.32 m3 / s, which differs from the design data by less than 1% and indicates the accuracy and reliability of the obtained data.

Hydraulic performance benchmarking for effective management of water distribution networks: An innovative composite index-based approach

Hydraulic performance assessment and benchmarking of water distribution networks (WDNs) impose a major challenge to water utilities worldwide. Presently, benchmarking strategies for WDNs are not fully developed, especially for analyzing intermittent systems commonly encountered in non-developed nations. To overcome these limitations, this paper proposes an index-based benchmarking strategy for WDNs, comparing their actual hydraulic performance and expected serviceability. A robust Hydraulic Performance Index (HPI) is developed as a global metric to account for the combined impact of multiple hydraulic outputs, concerning their benchmark values. The applicability of this index is verified on a numerical benchmark network, and its usefulness is demonstrated on a real-world intermittent WDN located in Kolkata (India) by coupling the HPI-based framework with hydraulic models using the EPANET-MATLAB programmer's toolkit. A scenario-based analysis is conducted using extended-period simulation to obtain the HPI for diverse service levels and leakage conditions of the WDN models. The HPI is designed to effectively capture the localized pressure reduction during peak flow, prioritize hydraulic outputs based on regional constraints, and penalize systems with unsustainably high hydraulic output. The developed strategy is also effective in performance benchmarking of WDNs of different nations with diverse serviceability and threshold parameters on a common platform. Finally, the practical efficacy and generalizability of the HPI-based results in the context of case-specific performance management of WDNs, along with limitations, recommendations and future perspectives are elucidated upon.

Numerical Modeling of the Effects of Toe Configuration on Throughflow in Rockfill Dams

The rockfill toe structure situated within the downstream slope of rockfill dams is an integral part of a defense mechanism safeguarding the dam structure in throughflow situations. Recent studies have concluded that the rockfill toe structure can have significant impacts on throughflow development and stability of rockfill dams under scenarios of accidental throughflow caused by overtopping of the dam core. The ability to numerically model the effect of various toe configurations on flow through rockfill dams can support the design of effective toe drainage structures for rockfill dams. Development and calibration of a reliable numerical modeling tool in this regard has been challenging owing to lack of availability of extensive datasets from physical modeling investigations. This study further employs datasets gathered by a recent physical modeling study investigating the effects of various toe configurations on throughflow development in rockfill dam models. A commercial numerical seepage modeling tool with an option for non-Darcy flow was calibrated against the datasets with good calibration metrics. The study is novel in providing a rare report on the usage of this option. The calibrated tool can further be employed to carry out a wide array of simulations to arrive at an ideal design for a toe structure for rockfill dams and for assessment of hydraulic performance of toe structures.

A stochastic framework for hydraulic performance assessment of complex water distribution networks: Application to connectivity detection problems

This paper is concerned with the hydraulic performance assessment of large scale water distribution networks in presence of uncertainty. In particular, the associate connectivity detection problem is examined in detail. For this purpose, a Bayesian system identification methodology is combined with an efficient hydraulic simulation model. A number of hydraulic model classes are defined as potential connectivity events. Based on information from flow rates in the pipes, the proposed updating technique provides estimates of the most probable connectivity scenarios. Such scenarios correspond to the model classes that maximize their evidences or posterior probabilities. The effectiveness of the proposed identification framework is illustrated by applying the connectivity detection approach to a real water distribution system.

Hydraulic Performance Assessment of Mychew Small Scale Irrigation Scheme, North Ethiopia

Performances assessment of irrigation schemes network is very essential in taking different water management strategies. However, the performance of Mychew irrigation scheme was not assessed and hence, this research was undertaken to assess the hydraulic performance of Mychew small scale irrigation scheme. Moreover, identification of the cause and effect for mal-functionality of irrigation structures was also another objective of this study. Hence, comprehensive field observations, measurements and focus group discussions were held to investigate hydraulic performance, cause and effect of failed hydraulic structures. Simple descriptive statistics was employed for analysis of the data collected from focus group discussions and observations. Eight performance indicators were used to assess the performance of this irrigation scheme. Several factors such as sedimentation, design problem, damage of sluice gates, abstraction of irrigation water by unwanted plants has been identified for mal-functionality of different structures. There were problems in irrigation adequacy (0.75) and equity (0.28) of irrigation water was categorized as poor, while good and fair for dependability (0.08) and irrigation efficiency (0.79), respectively. The average water surface elevation ratio, delivery performance ratio, and delivery duration ratio of the main canal during the monitoring period was less than one, greater than 5% and 150%, respectively. The highest sediment accumulation was observed at head and middle reaches of the irrigation scheme than the tail reaches. Generally, there were a number of irrigation structures which was mal-functioned in this irrigation scheme. Now it needs sustainable solution to improve the performance of the irrigation scheme. Therefore, it was recommended that water should be fairly distributed spatially and temporally. Additionally, capacity building and awareness creation to concerned bodies holds the key to bring a difference in irrigation water management in this irrigation scheme.

An experimental study on hydraulic and thermal performances of hybrid nanofluids in mini-channel

In the present work, the thermo-physical properties and hydraulic and thermal performances of alumina/water, silica/water, and alumina–silica/water nanofluids were experimentally investigated. The thermal conductivity and dynamic viscosity of nanofluids were measured for the volume fractions in the range of 0–2% and the temperature in the range of 10–40 °C. Some new correlations were proposed for the hybrid nanofluid. Single and hybrid nanofluids at the volume fractions of 0.05%, 0.1%, and 0.2% and the Reynolds number in the range of 490–3100 were tested in a mini-channel. Measurements of the thermo-physical properties indicated that the hybrid nanofluid provided larger values of the thermal conductivity and viscosity in comparison with the single ones. The results also showed that the Nusselt number increased with increasing the Reynolds number and volume fraction of the nanoparticles for all nanofluids. Hybrid nanofluid with 75% alumina–25% silica and volume fraction of 0.2% and the single alumina nanofluid with volume fraction of 0.2% provided the highest and the lowest increments in the Nusselt number with the mean increment values of 46% and 11%, respectively. The hydraulic performance assessment revealed that adding nanoparticles to the base fluid increased the friction factor in the mini-channel from 10.4 to 65.2% based on the values of the volume fraction. However, the thermal performance evaluation criteria are always above the unity regardless the type of the nanofluid and among the nanofluids considered in this study, and the maximum performance evaluation criterion was recorded for the hybrid nanofluid with the value of 1.23 at volume fraction of 0.2%.

Operational Evaluation of a Small Hydropower Plant in the Context of Sustainable Development

Proper design of hydrotechnical structures should meet the basic principles of sustainable development, i.e., the investment should be designed and made in technical terms, in accordance with the applicable standards and regulations, provide certain economic benefits and guarantee the absence of environmental hazards. The article examines the work of a Small Hydropower Plant (SHP) in Jaracz in technical and hydraulic terms. It also provides the analysis of the effect of changes in parameters such as water head, flow rate velocity, and shape of trash rack bars on expected SHP profits. The assessment of hydraulic performance consisted of investigating the impact of reduced flow rate and water head on power output and energy production. The analyses were carried out for the Francis turbine installed in the facility. Since the loss of channel capacity is shaped by plant debris accumulated on trash racks, the hydraulic performance assessment was extended to include the analysis of the species and weight composition of such accumulation on fine trash racks located in the inlet channel. Field research involved collecting organic material from the growing season (spring, summer) and post-growing season (autumn). Technical conditions were developed on the basis of the current technical condition of the inlet channel; there were also made simulations of its deteriorating state, as well as its impact on the received energy and economic benefits.

Hydraulic Performance Assessment of Sprinkler Irrigation with Rotating Spray Plate Sprinklers in Indoor Experiments

AbstractA recently developed rotating spray plate sprinkler (RSPS) with a six-grooved plate (R 3000) is evaluated in this paper. A set of nozzles numbered 15/128  in. (2.98 mm), 17/128  in. (3.37 m...

Flow boiling of R245fa in the brazed plate heat exchanger: Thermal and hydraulic performance assessment

Present study deals with the flow boiling of R245fa, a commercial working fluid used in organic Rankine cycle, in brazed plate heat exchanger with chevron angle of 45degree and 60degree. The effects of the heat flux, mass flux rate of refrigerant, saturation temperature on convective heat transfer coefficients are investigated. The operating conditions of the experiment are as mass flux: 30–40kgm−2s−1 quality at evaporator inlet: 0.1–0.8, heat flux: 2–15kWm−2. The heat transfer result suggests a nucleate boiling dominant process in the evaporator. The convective heat transfer coefficient showed a strong dependence on the heat flux and vapor quality at evaporator inlet. Moreover convective heat transfer coefficient show a linear relationship with mass flux of the refrigerant. It is worth mentioning that heat transfer coefficient is higher at higher saturation temperature and chevron angle. Based on the experimental data, empirical correlations were developed for the prediction of heat transfer coefficients and frictional pressure drop of refrigerant R245fa in brazed plate heat exchanger.

Hydraulic Performance Assessment of Lesa at low Pressure

AbstractTo assist with the selection of appropriate low elevation spray application (LESA) technology, hydraulic performance tests at low pressure were conducted. The main structural parameters in this study were the aboveground height (A), spacing between the sprinklers (B), travel speed (C), and sprinkler nozzle diameter (D). An orthogonal array with four factors and three levels was selected, and the direct analysis technique was used to analyze the test data. Results show that the influencing factors in decreasing order of importance were as follows: CDBA for application depth; BACD for irrigation uniformity (CU); ACBD for application efficiency; CDBA for surface runoff; and CDBA for soil water content. The highest application efficiency obtained during the experiments was 95.1%, and the highest uniformity coefficient obtained was 96.4%. The application efficiency was high when the sprinkler height was low. CU was high when the spacing between the sprinklers was small. The surface runoff amount was low when the travel speed was high. The application depth and surface runoff were higher when the sprinkler nozzle diameter was larger. Copyright © 2016 John Wiley & Sons, Ltd.

Discussion of “Assessment of Hydraulic Performance of Drip-Irrigation Emitters at Low Head Pressures” by Chao Zhang, Yaohu Kang, Shufang Jiang, Shuqin Wan, and Shiping Liu

Discussion of “Assessment of Hydraulic Performance of Drip-Irrigation Emitters at Low Head Pressures” by Chao Zhang, Yaohu Kang, Shufang Jiang, Shuqin Wan, and Shiping Liu

Hydraulic performance assessment of passive coal mine water treatment systems in the UK

Hydraulic performance assessment of passive treatment systems has been conducted for UK's Coal Authority mine water treatment systems. The study aims to improve the understanding of the hydraulic factors that govern contaminant behaviour, such that future design of treatment systems is able to optimise treatment efficiency and make performance more predictable, and improve performance over the long-term. Assessment of the hydraulic behaviour (i.e. residence time and flow pattern) of the treatment systems was accomplished by means of tracer tests. The tracer tests were undertaken at eight UK Coal Authority mine water treatment systems (lagoons and wetlands) within Northern England (main study areas) and part of southern Scotland. A modelling approach using a tanks-in-series (TIS) model was adopted to precisely analyse and characterise the residence time distributions (RTDs), in an effort to account for the different flow patterns across the treatment systems. Generally, lagoon RTDs are characterised by a greater flow dispersion compared to wetlands (i.e. higher dispersion number, D and lower number of TIS, n). Consequently, the hydraulic efficiency, eλ for lagoons is much lower than wetlands (mean of 0.20 for lagoons compared to 0.66 for wetlands). Implications for design and maintenance of mine water treatment systems are discussed.

Design, Construction and Hydraulic Performance Assessment of an Infiltration Gallery

The Alton Mill is located in Caledon, Canada, on a tributary of the Credit River that discharges into Lake Ontario. The Alton Mill initiative is aimed at conve…

Thermal hydraulic performance assessment of dual-cooled annular nuclear fuel for OPR-1000

► A thermal hydraulic performance of a 12 × 12 annular fuel array is evaluated. ► The subchannel analysis code for the dual-cooled annular fuel, MATRA-AF is validated. ► We evaluate the sensitivity for geometry tolerances and operating parameter. ► We decide the essential design parameters to uprate the power generation by dual-cooled annular fuel. ► A thermal margin amount accommodating a 20% power-uprate seems viable. An internally and externally cooled annular fuel was proposed for an advance PWR, which can endure substantial power uprating. KAERI is pursuing the development for a reloading of power uprated annular fuel for the operating PWR reactors of OPR-1000. In this paper, the characteristics and verification of the MATRA-AF are described. The thermal hydraulic performance of a 12 × 12 annular fuel is calculated for the major design parameters and its performance is compared against the reference 16 × 16 cylindrical fuel assembly. In particular, the enhancements of the thermal hydraulic performance of dual-cooled annular fuel are estimated for the 100% normal power reactor core. The purpose of this study is to estimate a normal power for OPR-1000 with dual-cooled annular fuel, and ultimately to assess the feasibility of 120% core power. The parametric study was carried out for the fuel rod dimension, gap conductance, thermal diffusion coefficients, and pressure loss of the spacer grids. As a result of the analysis on the nominal power, annular fuel showed a sufficient margin available on DNB and fuel pellet temperature relative to cylindrical fuel. The margin amount seems accommodating a 20% power-uprate seems viable.