International Journal of Advanced Design and Manufacturing Technology
Volume:5 Issue: 1, Mar 2012

Impeller trimming is a proper way to alter the performance of centrifugal pump with a constant speed so as to meet the demand on the specified flow rate and head in pumping systems. The affinity law accounting for the impeller trimming is the key relation to determine the pump performance with a trimmed impeller. There seems no experimental study dealing with such an affinity law for centrifugal oil pump handling water and viscous oils. In this paper, an experimental investigation into the performance of an industrial centrifugal oil pump of type 65Y60 was explored when the original impeller was trimmed four times. In the experiments water and viscous oils served as the working liquid, respectively. The trimming exponents at both best efficiency and shut-off points were worked out, and compared to those in the existing affinity law for impeller diameter reduction and water. These exponents are very helpful for engineers to determine a trimmed impeller diameter for centrifugal oil pumps handling water and viscose oils with a relative high viscosity. Meanwhile the “rising-efficiency effect” was revealed when a trimmed impeller is delivering highly viscous oils.

Oil and gas transmission pipelines are critical items of infrastructure in providing energy sources to regions and countries. Steel pipes are commonly used which can be subject to both internal and external corrosion. This paper presents an advanced nondestructive inspection technique for detection of oil-gas pipeline corrosion defect. The Pulsed Eddy Current (PEC) method has been successfully applied in corrosion detection of unburied gas pipeline without removing the insulation. First, the principles of pulse eddy current method is pointed out then, the pulsed eddy current test on a pipe is simulated by Maxwell software to obtain optimum test parameters. To test the new technique, some artificial defects are fabricated on the inner surface of a gas pipe to simulate different corrosions phenomena in practice. Three isolation layers are applied to the pipe in order to show the efficiency of PEC in the detection of wall thinning areas without removing the insulation.

A continuously variable transmission (CVT) is a transmission which may change step less by way of an infinite variety of effective gear ratios between maximum and minimum values. This contrasts with different mechanical transmissions that solely permit just a few different distinct gear ratios to be selected. Continuously variable transmissions (CVTs) are mechanical devices that allow a continuous variation of the output velocity by adjusting its geometrical configuration. This offers several advantages over traditional transmissions such as better fuel efficiency, quieter operation, and a lower mass. Current efforts to reduce the vehicles, fuel consumption in order to protect the environment and save fuel have seen a recent resurgence in CVT research, especially in the automotive industry. The torque of the continuously variable transmission system with friction drive mechanism is transmitted by contacting roller with input and output disks. For the higher transmitted torque, it is necessary to apply large load in order to get higher friction force, which in turn generates severe high stress on the contact surfaces of roller and disks. The toroidal type CVT system has simple component arrays that have three contact points between roller and each input or output disk to get the torque transmitted This work documents a successfully developed experimental model of a toroidal continuously variable transmission (CVT) by adjusting its geometrical configuration of CVT design and compared the experimental results of speed, torque and power delivered at the output disc with those obtained by a theoretical.

The current study presents a new analytical method for buckling analysis of rectangular and annular beams made up of functionally graded materials with constant thickness and Poisson’s ratio. The boundary conditions of the beam are assumed to be simply supported and clamped. The stability equations were obtained by using conservation of energy. The critical buckling load and first mode shape were obtained using Variational Calculus method. Increasing in buckling capacity and improvement in the behavior of functionally graded beams in comparison to homogenous beams have been investigated. After simplifying results, Duffing differential equation for homogeneous beam without oscillations was obtained and validity of this new work was proved.

This work presents a numerical study to investigate the heat transfer characteristics of a 2-D rectangular composite porous radiant burner (CPRB). In the construction of porous burner, the porous layer is considered to be of composite type consisting of upstream and downstream layers with equal thickness but with different physical and radiative properties. In the present work, a two dimensional rectangular model is used to solve the governing equations for porous medium and gas flow. In order to analyze the thermal characteristics of the CPRB, the coupled energy equations for the gas and porous medium are solved numerically and the discrete ordinates method is used to obtain the distribution of radiative heat flux in the porous media. Finally, the effects of various factors on the performance of CPRB are determined. Computational results show that high porosity and low scattering coefficient for downstream porous layer are desirable for maximizing the CPRB efficiency in comparison to a homogeneous one. Present results prove to be compatible with results obtained from previous studies.

On account of some complexities such as fluid-structure interaction and extra-large deformation problems, complete simulation of abrasive water jet cutting process is very hard. The main goal of this paper is to overcome these difficulties through comprehensive simulation in LS-DYNA commercial software. For this purpose the Smoothed Particle Hydrodynamics (SPH) and Arbitrary Lagrangian Eulerian (ALE) methods are employed. Utilizing these methods, the depth of water jet penetration and mechanism of erosion are simulated for a certain test case. In addition, the effect of water pressure and traverse speed on depth of penetration are examined. Comparison between the obtained results using both methods showed that the numerical results are in good agreement with available experimental data.

A new anti-lock braking system (ABS) for motorcycles is proposed in this study. It functions by processing the speed of the motorcycle tire in contact with the ground relative to the speed of the motorcycle itself and by calculating the slip ratio (λ) of the tire slipping on the ground while braking, and reducing it to a minimum which leads to increased controllability of the motorcycle and reduction of the stopping distance, especially when the ground is slippery. The design of the new ABS and its pilot model comprises mechanical parts, hydraulics, and an electrical circuit. The pilot model providing the testing facility for the brake system functioning in a fixed place is in fact a simulation of the movement of a motorcycle on the ground. When the electric motor is turned on, and its flywheel reaches the desired speed, a controllable load is applied to the flywheel by the motorcycle tire which is a modelling of the weight of the motorcycle and the rider. Then, by turning the electric motor off, the throttle is released and the brake is activated. In this state, without the tire being locked, it will stop within a shorter time and distance than the non-ABS, because the new system keeps the tire in the threshold state of slipping relative to the ground, which is the maximum friction coefficient and the maximum brake force. The results show that the stoppage time for the new ABS is about 40% less than that is the non-ABS type.

Fiber metal laminates are hybrid laminates consisting of thin alternating bonded layers of aluminum and fiber/epoxy. ARALL (Aramid aluminum laminate) and GALARE (glass fiber reinforced aluminum laminate) are specific kinds of fiber metal laminates that consist of thin aluminum sheets along with Kevlar/Epoxy and Glass/Epoxy composite layers, respectively. In this study, nonlinear tensile behavior of GLARE fiber metal laminates under in-plane loading conditions has been investigated. Due to the elastic-plastic behavior of aluminum layers, elastic analyses are not enough to accurately predict the tensile response. Thus, it is necessary to consider and explain the inelastic deformation behavior of GLARE laminates after yielding of aluminum alloy layers. Two appropriate analytical approaches, the orthotropic plasticity and modified classical laminated plate theories, have been used to predict the stress-strain response and deformation behavior of GLARE laminates. An acceptable agreement was observed between the two models. Results show that the GLARE behavior is almost bilinear under tensile loading condition and the tensile strength of unidirectional GLARE laminates are substantially stronger than aluminum alloys in the longitudinal direction.