scholarly journals Designing a Low Activation Pressure Drip Irrigation Emitter With Constraints for Mass Manufacturing

2016 ◽  
Author(s):  
Pulkit Shamshery ◽  
Amos G. Winter
Keyword(s):  
Drip Irrigation ◽  
Experimental Validation ◽  
Optimization Approach ◽  
Fluid Structure Interactions ◽  
Model Formulation ◽  
Flow Rates ◽  
Design Variables ◽  
Lower Activation ◽  
Drip Irrigation Emitter ◽  
Practical Constraints

This work discusses the modeling and optimization of a drip irrigation emitter for reducing activation pressure. Our model formulation focuses on analytically characterizing fluid-structure interactions in an existing 8 liters per hour (lph) pressure-compensating online emitter. A preliminary experimental validation of the resulting model was performed for three different emitter architectures. This model was used as a basis for a genetic algorithm-based optimization algorithm that focused on minimizing activation pressure. The design variables considered in our formulation include, geometric features of the emitter architecture, and practical constraints from manufacturing. We applied our optimization approach to four emitters (with flow rates of 4, 6, 7 and 8.2 lph) and were able to lower activation pressure by more than half in each case. The optimization results for all four emitters were experimentally validated in lab-studies. We performed a more exhaustive validation study for the 8.2 lph emitter with an emitter manufacturer. Results from these experiments (which followed ISO standards) showed that the optimized 8.2 lph emitter had a 75% lower activation pressure when compared to the original emitter design.

Frequency optimization of laminated functionally graded carbon nanotube reinforced composite quadrilateral plates using smoothed FEM and evolution algorithm

2017 ◽  
Vol 52 (14) ◽  
pp. 1971-1986 ◽  
Author(s):  
T Vo-Duy ◽  
T Truong-Thi ◽  
V Ho-Huu ◽  
T Nguyen-Thoi
Keyword(s):  
Carbon Nanotube ◽  
Optimization Problem ◽  
Volume Fraction ◽  
Differential Evolution Algorithm ◽  
Composite Plates ◽  
Functionally Graded ◽  
Optimization Approach ◽  
Reinforced Composite ◽  
Design Variables ◽  
Evolution Algorithm

The paper presents an efficient numerical optimization approach to deal with the optimization problem for maximizing the fundamental frequency of laminated functionally graded carbon nanotube-reinforced composite quadrilateral plates. The proposed approach is a combination of the cell-based smoothed discrete shear gap method (CS-DSG3) for analyzing the first natural frequency of the functionally graded carbon nanotube reinforced composite plates and a global optimization algorithm, namely adaptive elitist differential evolution algorithm (aeDE), for solving the optimization problem. The design variables are the carbon nanotube orientation in the layers and constrained in the range of integer numbers belonging to [−900 900]. Several numerical examples are presented to investigate optimum design of quadrilateral laminated functionally graded carbon nanotube reinforced composite plates with various parameters such as carbon nanotube distribution, carbon nanotube volume fraction, boundary condition and number of layers.

Design Optimization of RML Glove for Improved Grasp Performance

2018 ◽  
Author(s):  
Teja Vanteddu ◽  
Bijo Sebastian ◽  
Pinhas Ben-Tzvi
Keyword(s):  
Design Optimization ◽  
Daily Living ◽  
Experimental Validation ◽  
Large Diameter ◽  
Future Research ◽  
Linkage Mechanism ◽  
Design Variables ◽  
Wide Range ◽  
Optimal Values ◽  
Optimal Set

This paper describes the design optimization of the RML Glove in order to improve its grasp performance. The existing design is limited to grasping objects of large diameter (> 110mm) due to its inability in attaining high bending angles. For an exoskeleton glove to be effective in its use as an assistive and rehabilitation device for Activities of Daily Living (ADL), it should be able to interact with objects over a wide range of sizes. Motivated by these limitations, the kinematics of the existing linkage mechanism was analyzed in detail and the design variables were identified. Two different cost functions were formulated and compared in their ability to yield optimal values for the design variables. The optimal set of design variables was chosen based on the grasp angles achieved and the resulting mechanism was simulated in CAD for feasibility testing. An exoskeleton mechanism corresponding to the index finger was manufactured with the chosen design variables and detailed experimental validation was performed to illustrate the improvement in grasp performance over the existing design. The paper ends with a summary of the experimental results and directions for future research.

A Numerical Study on the Sensitivity of the Discrete Element Method for Hopper Discharge

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
H. Kruggel-Emden ◽  
S. Rickelt ◽  
S. Wirtz ◽  
V. Scherer
Keyword(s):  
Discrete Element Method ◽  
Numerical Study ◽  
Discrete Element ◽  
Tangential Direction ◽  
Flow Properties ◽  
Friction Coefficients ◽  
Flow Rates ◽  
Design Variables ◽  
Side Walls ◽  
Element Method

Based on the time-driven discrete element method, granular flow within a hopper is investigated. The main focus is thereby set on hopper vessel design variables such as discharge rates and applied wall pressures. Within the used model contacts are assumed as linear viscoelastic in normal and frictional-elastic in tangential direction. The hopper geometry is chosen according to Yang and Hsiau (2001, “The Simulation and Experimental Study of Granular Materials Discharged From a Silo With the Placement of Inserts,” Powder Technol., 120(3), pp. 244–255), who performed both experimental and numerical investigations. The considered setup is attractive because it involves only a small number of particles enabling fast modeling. However, the results on the experimental flow rates reported are contradictory and are afflicted with errors. By an analysis of the hopper fill levels at different points of time, the correct average discharge times and flow rates are obtained. Own simulation results are in good agreement with the experimental flow rates and discharge times determined. Based on the thereby defined set of simulation parameters, a sensitivity analysis of parameters such as friction coefficients, stiffnesses, and time steps is performed. As flow properties, besides the overall discharge times, the discharge time averaged axial and radial velocity distributions within the hopper and the normal stresses on the side walls during the first seconds of discharge are considered. The results show a strong connection of the friction coefficients with the discharge times, the velocity distributions, and the stresses on the side walls. Other parameters only reveal a weak often indifferent influence on the studied flow properties.

scholarly journals LAYOUT AND DESIGN SOLUTIONS OF FILTERING WATER INTAKES FROM SHALLOW WATERCOURSES FOR DRIP IRRIGATION SYSTEMS

2021 ◽  
Author(s):  
A. S. Shtanko ◽  
◽  
V. N. Shkura ◽  
Keyword(s):  
Water Intake ◽  
Drip Irrigation ◽  
Agricultural Development ◽  
Drainage Water ◽  
Low Flow ◽  
Mountain Streams ◽  
Irrigation Systems ◽  
Flow Rates ◽  
Hydrographic Features ◽  
Sand And Gravel

Purpose: development of layout and design schemes for low-flow water intakes, arranged on shallow river and stream watercourses for supplying water to drip irrigation systems. Agricultural development of terraces and floodplains of small foothill and mountain streams actualizes the development of facilities for water intake from them for the purpose of irrigating land. Morphological and hydrographic features, including shallow low-water depths, high flow rates, flow rates variability, saturation with sediments, the presence of underflow and overflow runoff, etc., make water intake from such watercourses difficult and specific. These circumstances predetermine the relevance of water intake structures development corresponding to the specified conditions. Materials and Methods. When developing the layout and design schemes of low-flow water intakes from shallow watercourses, the technologies of exploratory design of engineering systems and structures were used. Results. With regard to the morphometric, hydrological and other conditions of shallow foothill and mountain streams, a water intake with a bottom water intake was adopted for development. The water intake part of headworks is designed in the form of a toe drain, which has under-flow and overflow intake parts that allow water intake from the channel and off-channel water streams. The toe is made of two or three layers of sand and gravel material. Drainage pipes or pipe filters are used as a drainage element. Depending on the conditions of the watercourse, water intakes with transverse, longitudinal and pocket-coastal placement of water intakes are proposed. Conclusion. The layout and design schemes of filtering water intakes from shallow watercourses based on the use of overflow, underflow and combined structures of multilayer drainage water intakes with stream (transverse and longitudinal) and off-channel (pocket-coastal) placement have been proposed and developed.

Optimization of an Axial Turbine Stage for Aerodynamic Inlet Blockage

2011 ◽  
Author(s):  
Mohammad Arabnia ◽  
Vadivel K. Sivashanmugam ◽  
Wahid Ghaly
Keyword(s):  
Pressure Loss ◽  
Suction Side ◽  
Loss Coefficient ◽  
Von Mises Stress ◽  
Optimization Approach ◽  
Design Point ◽  
Pressure Loss Coefficient ◽  
Design Variables ◽  
Blade Shape ◽  
Von Mises

This paper presents a practical and effective optimization approach to minimize 3D-related flow losses associated with high aerodynamic inlet blockage by re-stacking the turbine rotor blades. This approach is applied to redesign the rotor of a low speed subsonic single-stage turbine that was designed and tested in DLR, Germany. The optimization is performed at the design point and the objective is to minimize the rotor pressure loss coefficient as well as the maximum von Mises stress while keeping the same design point mass flow rate, and keeping or increasing the rotor blade first natural frequency. A Multi-Objective Genetic Algorithm (MOGA) is coupled with a Response Surface Approximation (RSA) of the Artificial Neural Network (ANN) type. A relatively small set of high fidelity 3D flow simulations and structure analysis are obtained using ANSYS Workbench Mechanical. That set is used to train and to test the ANN models. The stacking line is parametrically represented using a quadratic rational Bezier curve (QRBC). The QRBC parameters are directly related to the design variables, namely the rotor lean and sweep angles and the bowing parameters. Moreover, it results in eliminating infeasible shapes and in reducing the number of design variables to a minimum while providing a wide design space for the blade shape. The aero-structural optimization of the E/TU-3 turbine proved successful, the rotor pressure loss coefficient was reduced by 9.8% and the maximum von Mises stress was reduced by 36.7%. This improvement was accomplished with as low as four design variables, and is attributed to the reduction of 3D-related aerodynamic losses and the redistribution of stresses from the hub trailing edge region to the suction side maximum thickness area. The proposed parametrization is a promising one for 3D blade shape optimization involving several disciplines with a relatively small number of design variables.

scholarly journals Modeling the future of irrigation: A parametric description of pressure compensating drip irrigation emitter performance

PLoS ONE ◽  
2017 ◽  
Vol 12 (4) ◽  
pp. e0175241 ◽  
Author(s):  
Pulkit Shamshery ◽  
Ruo-Qian Wang ◽  
Davis V. Tran ◽  
Amos G. Winter V
Keyword(s):  
Drip Irrigation ◽  
The Future ◽  
Parametric Description ◽  
Drip Irrigation Emitter

A fast multiobjective optimization approach to S-duct scoop inlets design with both inflow and outflow

2018 ◽  
Vol 233 (9) ◽  
pp. 3381-3394
Author(s):  
Lifang Zeng ◽  
Dingyi Pan ◽  
Shangjun Ye ◽  
Xueming Shao
Keyword(s):  
Multiobjective Optimization ◽  
Total Pressure ◽  
Optimization Method ◽  
Navier Stokes ◽  
Integral Model ◽  
Optimization Approach ◽  
Navier Stokes Equation ◽  
Cross Sectional ◽  
Design Variables ◽  
Computational Fluid Dynamics Analysis

A fast multiobjective optimization method for S-duct scoop inlets considering both inflow and outflow is developed and validated. To reduce computation consumption of optimization, a simplified efficient model is proposed, in which only inflow region is simulated. Inlet pressure boundary condition of the efficient model is specified by solving an integral model with both inflow and outflow. An automated optimization system integrating the computational fluid dynamics analysis, nonuniform rational B-spline geometric representation technique, and nondominated sorting genetic algorithm II is developed to minimize the total pressure loss and distortion at the exit of diffuser. Flow field is numerically simulated by solving the Reynolds-averaged Navier–Stokes equation coupled with k–ω shear stress transport turbulence model, and results are validated to agree well with previous experiment. S-duct centreline shape and cross-sectional area distribution are parameterized as the design variables. By analyzing the results of a suggested optimal inlet chosen from the obtained Pareto front, total pressure recovery has increased from 97% to 97.4%, and total pressure distortion DC60 has decreased by 0.0477 (21.7% of the origin) at designed Mach number 0.7. The simplified efficient model has been validated to be reliable, and by which the time cost for the optimization project has been reduced by 70%.

Thermosyphon Models for Downhole Heat Exchanger Applications in Shallow Geothermal Systems

1978 ◽  
Vol 100 (4) ◽  
pp. 713-719 ◽  
Author(s):  
D. B. Kreitlow ◽  
G. M. Reistad ◽  
C. R. Miles ◽  
G. G. Culver
Keyword(s):  
Heat Exchanger ◽  
Analytical Models ◽  
Geothermal Systems ◽  
Flow Rates ◽  
Estimated Parameters ◽  
Design Variables ◽  
Circulation Mechanism ◽  
Geothermal Wells ◽  
Experimental Values ◽  
Theoretical Results

The analysis of downhole heat exchangers used to extract energy from relatively shallow geothermal wells leads to the consideration of several interesting problems of buoyancy-driven heat transfer in enclosures. This paper considers thermosyphoning through and around the wellbore casing which is perforated at two or more depths. Analytical models are developed for thermosyphoning in the cased well both with and without a heat exchanger installed. Theoretical results are compared with experimental values. These comparisons show that the observed energy extraction rates and flow rates through the well casing are possible with thermosyphoning as the only circulation mechanism within the well bore. The model with a heat exchanger installed is parametrically evaluated to illustrate the sensitivity of the model to estimated parameters and the effect of changes in design variables or constraints.

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