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hydraulics
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Experimental investigation on improvement of wet cooling tower efficiency with diverse packing compaction using ann-pso algorithm
, Article Energies ; Volume 14, Issue 1 , 2021 ; 19961073 (ISSN) ; Soltani, M ; Shahali, P ; Moradi Kashkooli, F ; Larizadeh, R ; Raahemifar, K ; Adibi, M ; Ghasemi, B ; Sharif University of Technology
MDPI AG
2021
Abstract
In this study, a numerical and empirical scheme for increasing cooling tower performance is developed by combining the particle swarm optimization (PSO) algorithm with a neural network and considering the packing’s compaction as an effective factor for higher accuracies. An experimental setup is used to analyze the effects of packing compaction on the performance. The neural network is optimized by the PSO algorithm in order to predict the precise temperature difference, efficiency, and outlet temperature, which are functions of air flow rate, water flow rate, inlet water temperature, inlet air temperature, inlet air relative humidity, and packing compaction. The effects of water flow rate,...
Fabrication of a highly efficient new nanocomposite polymer gel for controlling the excess water production in petroleum reservoirs and increasing the performance of enhanced oil recovery processes
, Article Chinese Journal of Chemical Engineering ; Volume 32 , 2021 , Pages 385-392 ; 10049541 (ISSN) ; Ayatollahi, S ; ZareNezhad, B ; Sharif University of Technology
Materials China
2021
Abstract
A new nanocomposite polymer gel is synthesized for reduction of excess water production in petroleum reservoirs at real operating conditions. This new nanocomposite gel contains SiO2 nanoparticles, partially hydrolyzed polyacrylamide (HPAM) and chromium triacetate. High pressure and high temperature tests using porous carbonate core are carried out to evaluate the effects of nanoparticles on the synthesized polymer gel performance. It is shown that the residual resistance factor ratio of water to oil using the synthesized polymer gel nanocomposite in this work is much higher than that of the ordinary polymer gels. The presented results confirm the high performance of the synthesized...
Analysis of evaporating liquid bridge in horizontal fractures
, Article Journal of Petroleum Science and Engineering ; Volume 202 , 2021 ; 09204105 (ISSN) ; Ghazanfari, M.H ; Masihi, M ; Sharif University of Technology
Elsevier B.V
2021
Abstract
The formation of liquid bridge is pertinent to many fields including seepage into underground fractured rocks as an environmental issue and capillary continuity between matrix blocks which controls oil recovery in fractured reservoirs. Evaporation from the surface of liquid bridge into the surrounding gas could affect the stability of liquid bridge and fracture capillary pressure, which is not well discussed in the available literatures. In this research, by the aid of analogy between the diffusive flux and electrostatic potential, a new model for predicting evaporation rate from a liquid bridge inside a horizontal fracture is presented. The proposed model is then coupled with Young-Laplace...
Effects of inlet position and baffle configuration on the hydraulic performance of primary settling tanks
, Article 2005 ASME International Mechanical Engineering Congress and Exposition, IMECE 2005, Orlando, FL, 5 November 2005 through 11 November 2005 ; Volume 261 FED , 2005 , Pages 613-618 ; 08888116 (ISSN); 0791842193 (ISBN); 9780791842195 (ISBN) ; Tamayol, A ; Ahmadi, G ; ASME Fluids Engineering Division ; Sharif University of Technology
2005
Abstract
Circulation regions always exist in the settling tanks. These regions reduce the tank's performance and decrease effective volume of the tank. Recirculation zones would also result in short-circuiting and high flow mixing problems. Inlet position would also have effect on these, too. Using good baffle configuration may increase performance of settling tanks. One method for comparison of different tanks with each others is to use FTC. In this paper, by using FTC the effects of inlet position and baffle configuration on the hydraulic performance of primary settling tanks are studied. The best position of baffle is also determined. Copyright © 2005 by ASME
The effect of influent COD and upward flow velocity on the behaviour of sulphate-reducing bacteria
, Article Process Biochemistry ; Volume 40, Issue 7 , 2005 , Pages 2305-2310 ; 13595113 (ISSN) ; Ghavipanjeh, F ; Mirjafari, P ; Sharif University of Technology
2005
Abstract
The effect of up velocity and influent COD concentration on the activity of sulphate-reducing bacteria (SRB) in UASB reactors is discussed. To study these effects, four UASB reactors were built and utilized in parallel. Examinations were carried out in two different concentrations of molasses (500 mg COD/l and 1000 mg COD/l) and four different upward flow velocities. It was observed that at velocities greater than 1 m/h, SRB bacteria were easily washed out from the reactors due to lower density and lack of ability to form dense and firm granules. It was found that in low-strength wastewaters with a COD to sulphate ratio of 2, an upward velocity in the range of 1.5-2.5 m/h could be...
A hybrid pole climbing and manipulating robot with minimum DOFs for construction and service applications
, Article Industrial Robot ; Volume 32, Issue 2 , 2005 , Pages 171-178 ; 0143991X (ISSN) ; Zakerzadeh, M. R ; Vossoughi, G. R ; Bagheri, S ; Sharif University of Technology
2005
Abstract
Purpose - Aims to describe design, prototyping and characteristics of a pole climbing/manipulating robot with ability of passing bends and branches of the pole. Design/methodology/approach - Introducing a hybrid (parallel/serial) four degree of freedom (DOF) mechanism as the main part of the robot and also introduces a unique gripper design for pole climbing robots. Findings - Finds that a robot, with the ability of climbing and manipulating on poles with bends and branches, needs at least 4 DOFs. Also an electrical cylinder is a good option for climbing robots and has some advantages over pneumatic or hydraulic cylinders. Research limitations/implications - The robot is semi-industrial...
Experimental results of pressure variation in two-phase air-water flow in water tunnels
, Article 31st IAHR Congress 2005: Water Engineering for the Future, Choices and Challenges, 11 September 2005 through 16 September 2005 ; 2005 , Pages 6523-6533 ; 8987898245 (ISBN); 9788987898247 (ISBN) ; Byong-Ho J ; Sang I. L ; Won S. I ; Gye-Woon C ; Sharif University of Technology
Korea Water Resources Association
2005
Abstract
An experimental investigation has been carried out to verify characteristics of pressure fluctuations inside a circular, horizontal and inclined pipeline (90mm inside diameter and 10 m long) carrying two-phase air-water flow in a controlled manner (operating at room temperature and normal pressure). The pressure fluctuation was considered to be due to interaction between the fluid and air bubble compressibility in the pipe. The fluctuating pressure was studied in detail while the flow pattern was mainly slug, wavy or stratified flow. The tests were carried out varying with time, space, water flow rate/air flow rate ratio and pipe inclination. The pressure fluctuations were measured...
Two-dimensional model for lateral intake flows
, Article Proceedings of the Institution of Civil Engineers: Water Management ; Volume 158, Issue 4 , 2005 , Pages 141-150 ; 17417589 (ISSN) ; Taher Shamsi, A ; Sadeghi Bagheney, M ; Mohamadian, A ; Sharif University of Technology
ICE Publishing
2005
Abstract
This paper gives details of the refinement and application of a two-dimensional horizontal model for rivers. An explicit finite-difference algorithm was used for solving the governing differential equations, which includes the conservation of mass and momentum to predict hydrodynamic parameters. The model includes different turbulence closure models - that is, constant eddy viscosity, Prandtl simple mixing length and Smagorinsky methods. An experimental programme was designed and carried out in a laboratory flume to measure the length of eddy produced at the entrance of the intake. Model predictions have been compared with experimental results for a lateral intake. The effect of different...
Floating bridge modeling and analysis
, Article Scientia Iranica ; Volume 12, Issue 2 , 2005 , Pages 199-206 ; 10263098 (ISSN) ; Paein Koulaei, R. T ; Sharif University of Technology
Sharif University of Technology
2005
Abstract
This paper presents an overview of a study on the design and analysis aspects of the Lake Urmia Bridge in Iran. For years there have been several detailed investigations on this subject. Here, these alternatives are discussed and, then, results of analyses for a proposed solution, a floating bridge, are presented. These aspects include environmental loads, structure and the mooring system. © Sharif University of Technology
Design method and feasibility study of fully actively controlled frames
, Article Scientia Iranica ; Volume 11, Issue 1-2 , 2004 , Pages 50-59 ; 10263098 (ISSN) ; Asbmarz, M. M ; Sharif University of Technology
Sharif University of Technology
2004
Abstract
In this paper, results of a preliminary study on the feasibility of using an Active Tendon Control (ATC) mechanism for frame structures subject to earthquakes is presented. So far, the ATC mechanism has mainly been considered as a means for installation on structures to mitigate their response under severe loading. In this study, it is desired to evaluate the possibility of using the ATC mechanism to serve as the main means for the stability of frames against earthquakes. Hence, a methodology is presented for the integrated design of frames with ATC mechanisms, which is tested numerically. A number of five-, ten-, fifteen- and twenty-story steel frames are used for this purpose. To this end,...
Application of sensitivity analysis to the development of high performance adaptive hydraulic engine mounts
, Article Vehicle System Dynamics ; Volume 39, Issue 4 , 2003 , Pages 257-278 ; 00423114 (ISSN) ; Khajepour, A ; Durali, M ; Sharif University of Technology
2003
Abstract
In this paper, the sensitivity analysis is applied to the development of high performance adaptive hydraulic mounts. The analysis allows us to select the most effective design parameters for tuning an adaptive mount to different road and engine conditions. It is shown that in the low frequency road excitation, the upper chamber compliance and inertia of the fluid column in the inertia track are the most influential properties in changing the dynamic stiffness of the hydraulic mount. These properties for the high frequency engine excitations are the upper compliance and the inertia of the fluid column of the decoupler. For tuning the adaptive mount to different road and engine excitation, a...
Modeling and direction control of a 2 D.O.F. Heavy launching bed on a moving car using a full suspension model
, Article 2003 ASME Design Engineering Technical Conferences and Computers and Information in Engineering Conference, Chicago, IL, 2 September 2003 through 6 September 2003 ; Volume 5 B , 2003 , Pages 1677-1685 ; Afsharzadeh, A ; ASME ; Sharif University of Technology
American Society of Mechanical Engineers
2003
Abstract
In this paper dynamic modeling and direction control of a launching bed (L.B.) with 2 D.O.F. rotation around vertical and lateral axes, mounted on a vehicle moving on a rough road is investigated. The purpose of direction control is to bring the L.B. from any initial angle to a desired angle with respect to the reference frame and to keep it there. The vehicle model is a full car with bounce, yaw, roll and pitch degrees of freedom. The suspension system of the vehicle is considered to have passive elements and unsprung masses. The stiffness of the tires is also included in the model. To control the position of the launching bed, a servo-hydraulic system comprising of hydro-motors, gearboxes,...
Oblique rectangular sharp-crested weir
, Article Proceedings of the Institution of Civil Engineers: Water and Maritime Engineering ; Volume 156, Issue 2 , 2003 , Pages 185-191 ; 14724561 (ISSN) ; Vatannia, Z ; Ghodsian, M ; Jalili, M. R ; Sharif University of Technology
ICE Publishing
2003
Abstract
Among discharge flowmeters, the rectangular sharp-crested weir is one of the most popular and accurate, as well as being easy to work with. Using the standard weir, with the help of the conventional weir equation and Rehbock's or a similar standard formula for the discharge coefficient (Cd), the flow can be easily calculated. In order to increase the efficiency of the weir, it can be placed obliquely to the flow, increasing the effective weir length (L) and, hence, increasing the discharge for the same water head with the same channel width (B). The results of a comprehensive set of tests for oblique weirs (1·14 ≤ L/B ≤ 2·26 or oblique angles from 29° to 64°) show that for L/B less than 1·41...
A finite volume central differencing scheme for simulation of the shut down procedure of a hydraulic system
, Article International Journal of Fluid Power ; Volume 3, Issue 2 , 2002 , Pages 17-27 ; 14399776 (ISSN) ; Farahani, R. H ; Sharif University of Technology
2002
Abstract
A new central differencing finite volume scheme is investigated for solution of unsteady hydraulic problems as water hammer in pipe systems. Special time stepping procedure similar to Runge-Kutta algorithm is used to stabilize this second order scheme. It is monotonized by adding dissipative terms including second and fourth derivatives of the conserved variables, with coefficients proportional to derivatives of pressure or volumetric flow, which keeps the second order of accuracy in smooth flow regions. The one-dimensional unsteady incompressible equations are solved for a water hammer situation, and results are compared to existing analytical solutions. Results are also compared with...
Evaluation of hydraulic fracturing pressure in a porous medium by using the finite element method
, Article Energy Sources ; Volume 24, Issue 8 , 2002 , Pages 715-724 ; 00908312 (ISSN) ; Panah, A. K ; Pak, A ; Vaziri, H ; Islam, M. R ; Sharif University of Technology
2002
Abstract
Hydraulic fracturing is a complicated phenomenon in which deformation of the porous medium and fluid leak-off to the surrounding area take place simultaneously. Their interaction therefore must not be overlooked. Modeling of this phenomenon in isothermal conditions requires analysis of soil deformation and crack and pore fluid pressure interaction. In this paper, a numerical scheme is presented for analysis of soil stresses and deformations and fluid flow in a coupled manner. This scheme is also used to detect the fracture in the medium. Our model was used in simulating a set of hydraulic fracturing experiments. These experiments were performed on compacted hollow cylindrical specimens under...
Designing an Optimal Pumping Program for Multi-stage Hydraulic Fracturing Operation and Investigating the Effect of Different Parameters
, M.Sc. Thesis Sharif University of Technology ; Jamshidi, Saeed (Supervisor)
Abstract
With the production from the reservoirs, the amount of in-situ oil storage has decreased and there is a need to increase oil recovery (EOR) from the reservoir. Increased oil recovery (EOR) includes operations such as acidizing and hydraulic fracturing. Considering the economic and high operational costs and geomechanical complexities, as well as the technical progress of hydraulic fracturing and its future; It is necessary to manage hydraulic fracturing operations optimally. This research is about hydraulic fracturing and its main goal is to optimize the parameters of the fracture or the geometry of the fracture. The research study was carried out on the Bangistan Reservoir located in the...
Development of a Multi-functional Soil Column for Studying Bioremediation and Multiphase Flow
, M.Sc. Thesis Sharif University of Technology ; Sadeghi, Hamed (Supervisor)
Abstract
Soil and water pollution is one of the most common types of pollution in terrestrial and aquatic ecosystems. The development of mines and the oil and petrochemical industry on one hand and the non-compliance with environmental requirements on the other hand have caused large amounts of hydrocarbon pollutants and heavy metals to enter the environment in recent decades. Petroleum materials and heavy metals leak into the surrounding environment during drilling and extraction in oil sites and mines or during land and sea transportation, despite the measures taken to control their pollution. The conducted studies show that human industrial activities are the only cause of environmental pollution...
Development of a Computer Code for Thermo Hydraulics Analysis of Prismatic High Temperature Gas Cooled Reactors
, M.Sc. Thesis Sharif University of Technology ; Ghofrani, Mohammad Bagher (Supervisor) ; Jafari, Jalil (Supervisor)
Abstract
A prismatic high temperature gas-cooled reactor (HTGR), which is a graphite moderated, helium-cooled reactor, is a promising candidate for next generation nuclear power plant in that it enables applications, such as hydrogen production or process heat for petrochemical by supplying heat with core outlet temperatures as high as 1000°C. A Thermal Hydraulic Analysis Code (THAC) for gas-cooled reactors has been developed. THAC implicitly solves heat transfer equation of fuel, graphite block and helium. Three types of fuel pins were considered; solid fuel pin, fuel pins with inside holes and annular fuels with coolant flow from its inside and outside surfaces. THAC predicts axial and radial...
Development of a Computer Code for Thermal Hydraulic Design of a High Temperature Gas Cooled Reactor Core
, M.Sc. Thesis Sharif University of Technology ; Ghofrani, Mohammad Bagher (Supervisor) ; Jafari, Jalil (Supervisor)
Abstract
High temperature gas cooled reactors (HTGR) are one of the most promising reactors in the new generation of world commercial reactors. They are divided into two main categories: Prismatic gas cooled reactors and pebble bed gas cooled reactors. These reactors have many advantages, such as inherent safety, high thermodynamic efficiency and the possibility of producing hydrogen. One of the most important challenges in developing these reactors is providing appropriate codes in design and simulating their performance. Two codes have been developed in this thesis. The first, THFAM, is a steady state thermal hydraulic code which helps in analyzing a fuel assembly. The second, named THCM is...
Numerical Modeling of Stability and Transport of Soluble Contaminants in Tailings Dams under Coupled Hydro-Chemical Processes (A Case Study of Sarcheshmeh Tailings Dam)
, M.Sc. Thesis Sharif University of Technology ; Sadeghi, Hamed (Supervisor)
Abstract
The instability and contamination leakage through tailings dams is one of the major problems of them. These dams are usually constructed through self-consolidation with minimum compaction effort, so special attention must be given to the stability of these structures. In addition, tailings dams contain considerable amounts of metals and chemically soluble contaminants resulting from mining processes in their reservoirs, making them more likely to leak contamination from the dam's foundation and body, causing pollution downstream. The infiltration of various chemical contaminants into the soil may alter its hydraulic and resistance properties. Laboratory studies have shown that pore solution...