Sharif Digital Repository

This existing research has been conducted to reach quick evaluation instructions to pipe earthquake damages in the piping systems inside the industrial complexes. In the old complexes of such kinds there are cases where field inspections and quality evaluations are urgently required subject to peculiar conditions affecting each piping system inside the units and in certain cases subject to lack of access to the as built-drawings. However, so far any definite instruction hasn’t been available for a quick evaluation of likely damages in piping system: all because of various pipe types, complexity of pipes geometry, different temperatures and pressures in different sections. In this research... 

Water hammer is a pressure surge or wave resulting when a pressurized fluid in motion is forced to stop or change direction suddenly. This phenomenon can cause great amount of damage to the system and should be considered in designing of pipe systems. So, researchers have derived and proposed numerous models using different approaches. In this study a one-dimensional model using Time Splitting Method (TSM) and Double Sweep Method (DSM) are proposed to simulate transient flow in deformable pipes in networks. To solve the equations of momentum and continuity TSM is applied. In addition Brunone model is used to study the effect of unsteady friction on water hammer wave shape and attenuation. To... 

Several SPD methods have been invented for processing rods and sheets, and their physical and mechanical properties have been investigated so far. The materials processed by these methods have not been industrialized thoroughly. Moreover, in previous investigations, few works have been carried out on tubular types of materials. Thus, in this study, aluminum tube goes through a tubular channel in order to achieve different values of strains. This method is named Tube Channel Pressing. The mechanical and microstructural investigations on aluminum tubes which have been processed up to 5 passes shows that ultimate strength increases 1.7 times and sub-grains size reaches to 360 nm. Applying final... 

In the present study, design and manufacturing of a connected pipe liquid fuel ramjet test platform is implemented for performance investigation of a research liquid fuel ramjet burner in the thermodynamic flight conditions. Design and manufacturing of platform systems include: the hot air supply system, the liquid fuel system and the square cross-sectional combustion chamber with the v-gutter shape flame holder. In order to determine the performance range of subsystems, calibration process has been carried out. Calibration process of the hot air supply system includes: determining of the burner inlet velocity and temperature. Also, calibration of the liquid fuel system includes: determining... 

Pipeline systems are one of the cheapest ways for distribution and transportation of petroleum and natural gas. The testing of pipes used in the petroleum industry is necessary to avoid unplanned process interruptions, environmental pollution and provide good safety. One of the methods which is used for pipeline inspection is the ultrasonic non-destructive testing (NDT) technique. The use of conventional NDT techniques such as ultrasonic thickness gauging is a slow inspection process, which becomes very expensive when full inspection is needed. Ultrasonic guided waves provide an appropriate fast screening technique. These waves stress the whole pipe wall and propagate along the length of the... 

Rapid growing use of energy resources in recent decades, caused to focus on combined heat and power generation systems according to their high efficiencies. Energy efficiencies with these technologies will be up to 90 percent. Some benefits of Co-generation systems are their high efficiencies, omitting of transmission and distribution lossesin the electricity grid, fuel consumption reduction, moving to ward privatization,independent and decentralized production of electricity and heat, increase competition in the power generation and reduction theemission of greenhouse gases, particularly carbon dioxide. In This article theeconomicsof combined heat and power generator stobe installed... 

Improving efficiency of heat exchangers has always been an important concern for the industry. Pulsating Heat Pipes (PHPs) are novel and efficient technology in the field of heat transfer. PHPs are widely used in solar water heaters, solar desalination systems, etc. In this research, thermal performance of Open Loop Pulsating Heat Pipes (OLPHPs) using three different ferrofluids (ferrofluid without surfactant and nanoparticles’ coating, ferrofluid with coating of nanoparticles, and ferrofluid with surfactant) is experimentally investigated. In addition, effects of charging ratio (20, 40, 60, and 80%), heating power (20, 30, 40, 50, 60, 70, 80, 100, 120, 140, 160, 180, 200, 240, 280, 320,... 

Nowadays, there is rapid development of practical engineeringsolutions to a multitude ofheating problems. Heat generated inmicro-devices used in manufacturing and electronics require specialsolutions. Pulsating Heat Pipes (PHPs) are novel and efficient technology in the field of heat transfer and previous researches show that using ferrofluid (magnetic nanofluid) in Pulsating Heat Pipes (PHPs) enhances the thermal performance in comparison with the case of distilled water under certain conditions by applying magnetic fields and the performance is dramatically improved at horizontal heating mode. In this research an experimental setup for visualizing two phase flows in a flat-plate Pulsating... 

In the present study an air supply system of a connected-pipe ramjet test facility for liquid fuel ramjet engine in theoretical and numerical base designed and optimized that the purpose is for performance test of a ramjet engine combustor in flight condition. The flight condition gained from previous assessment that is 1.5 kg air in 10 bars and 550 K. Air supply subsystems consist of air tanks, compressors, valves, regulators, preheater, and fuel and oxygen systems that are designed in a preliminary process and then valves, orifices, and fuel and oxygen systems optimized by HYSYS program. In the last step preheater that is a gas turbine combustor investigated and possible changes made by... 

Developing of electric instruments with high performance needs high capacity heat transfer equipments. Pulsating heat pipes have better performance compared with normal heat pipes and can be used for cooling electronic instruments in near future. Also, one specific kind of heat pipes, which is called rotating pulsating heat pipe, can be used in cooling the turbine blades and every rotating device. Rotating pulsating heat pipe is a cooling device in which the pipes can rotate around the axis perpendicular to the plane of pipes. In this research one rotating heat pipe was built and the effects of heat input, filling ratio, working fluid and rotational acceleration were examined experimentally,... 

Improving efficiency of heat exchangers has always been an important concern for the industry. Pulsating heat pipes are novel and efficient technology in the field of heat transfer. Pulsating heat pipes are widely used in solar water heaters, solar desalination systems, air conditioning systems, cooling of electronical boards, etc. these applications explain the necessity of performing this study in our country. In this research, thermal performance of open loop pulsating heat pipes using two operating fluids (ferrofluid with surfactant and aluminum microfluid) is experimentally investigated. Start-up and steady thermal performance of pulsating heat pipes charged with these two operating... 

Buried pipelines as vital arteries,which will play a major role in human life should be designed and implemented in such a way that withstand the least possible harm with regard economic issues.In this study we tried to use a physical model, the impact of pipeline buried in soil slope under dynamic load are examined.To achive this goal we use a rigid metal bax with dimensions of 301.5*101.5*155 cubic meters for modeling. Pipes used in these experiments has a diameter of 1.6 cm which are connected by a fulcrum to the wall box. In order to measure strain generated in the pipe we use a series of strain gauges that were installed using the pipe at some points. Physical models made on Sharif... 

One of the important issues that increasing development of electronic systems has caused is how to transfer the generated heat out of the system. Heat pipes can transfer large amount of heat because of using latent heat of evaporation and condensation. In micro scales using micro heat pipes is popular that in this instrument liquid returns to evaporator by means of surface tension force. So numerical solution is essential for verifying experimental results and increasing performance of this instrument. In this research has been planned to develop a comprehensive model for numerical solution of flow and heat transfer in micro heat pipes. For this reason surface evaporation and …,... 

In this study the behavior of buried pipes under permanent ground deformation (PGD) ef-fects caused by reverse faulting is investigated by means of both experimental and numeri-cal approaches. A total number of 7 full-scale experiments on buried steel pipes subjected to a fault offset of 0.6 m along the slip plane is carried out and the effects of different pa-rameters such as pipe diameter (114.3 mm (4ʺ) and 168.3 mm (6ʺ)), burial depth (0.25m, 0.5m, 1 m) and soil type (SW and SM) on the response of the buried pipes are studied. Ex-perimental results show that the pipe deformation shape changes with increasing burial depth from half-sine (for shallow depths) to an S-shape (for moderate to... 

Regarding high importance of casing pipes in oil industry also considering that they have not been producing domestically (with specific features), the main object of this research is feasibility study of establishment of a casing pipe threading plant which produces such kind of pipes. Usage of Casing PipesIs defining as a separator between wall of oil well and its core. The operation starts with driving and fixing a casing pipe to the oil well to avoid its collapsing during excavation process , then next casing pipes will be driven to the well and will be fixed to the previous pipes. During current research, after gathering all related financial and technical data, evaluation of “Net... 

A major concern in directional well drilling is the transport mechanism of cuttings by drilling fluid. This thesis describes the effect of angular velocity and postbuckled vibrations of drillstring on cuttings transport in a directional well drilling. The analysis proceeds in two stages. First, a finite element model is used to predict the dynamic behavior of postbuckled drillstring inside a directional well. Second, a coupled Computational Fluid Dynamics and Discrete Element Method (CFD-DEM) approach to simulate the cuttings transport considering the dynamic collision process. In the combined computational fluid dynamics and discrete element method (CFD-DEM), the fluid phase is treated... 

Transportation of cuttings and efficiency of the hole cleaning has been one of the major concerns of stake holders in the oil and gas industry.This is because a successful drilling program is a key to a productive and profitable oil and gas business. A successful drilling program is as a result of an efficiently cleaned hole. On the other hand, a poor or inefficient hole cleaning implies accumulation of cuttings or formation of cuttings bed in the well. This often leads to decreased rate of penetration, increased cost of drilling, fractured formation, increased plastic viscosity of mud as a result of grinding of cuttings and stuck pipe. Hole cleaning is effected primarily with a drilling... 

Loop heat pipe (LHP) is a two phase heat transfer device that is mostly used in cooling spacecrafts facilities. In this research a novel LHP is studied analytically and its steady state operating characteristics is analyzed in a one dimensional approach with heat transfer and pressure drop correlations. The novel LHP has a new arrangement in evaporator and reservoir configuration in comparison with conventional LHPs, which results in a different energy and fluid flow. In addition, the novel LHP has a new mechanism for acive control of working temperature. In modeling the proposed LHP the fluid and energy flows are first determined, then proper correltaions for calculationg each energy flow... 

A Loop heat pipe (LHP) is an efficient two phase heat transfer device that is widely used in cooling applications. In this research a novel LHP was designed, fabricated and its performance was investigated through various experiments. The novel LHP has a new arrangement in evaporator and reservoir configuration in comparison with conventional LHPs, which results in a different energy and fluid flow. In addition, the novel LHP has a new mechanism for active control of working temperature which was not already used. Aside from its good performance, this LHP has easier and lower cost manufacturing process compared with the conventional ones. Also the proposed temperature control method is... 

A desired circulatory flow in flat-plate pulsating heat-pipes may improve electronic thermal management. This desired flow can be achieved by fabricating connecting channels (CCs) to increase flow resistance in one direction. In addition, connecting channels may increase the freedom degree of fluid. In order to investigate the effect of CC, two aluminum flat plate thermal spreaders with overall size 320mm×220mm×5mm - one with CC (CC-FPHP) and one without it- were fabricated. Both of the speaders have square channels with crosssection 2mm×2.8mm. The FPHPs were charged with ethanol as working fluid with filling ratios of 35%, 50%, 65%, and 80% by volume. Performance of connecting-channels in...