Tahsin Engin

Performance Characteristics of a Centrifugal Pump Impeller With Running Tip Clearance Pumping Solid-Liquid Mixtures

We present extensive results on the performance of an unshrouded centrifugal pump impeller handling solid-liquid mixtures. The effect of the clearance between the impeller tip and the casing and of the solid concentration, density and mean diameter on the pump performance characteristics is investigated. The results are discussed and utilized, together with data available in the literature, to establish a correlation allowing the prediction of the head reduction factor for shrouded/unshrouded impeller centrifugal pumps handling solid-liquid mixtures

Comparative Evaluation of Some Existing Correlations to Predict Head Degradation of Centrifugal Slurry Pumps

In order to optimally design a slurry transportation system, it is necessary to know how the presence of solids will change the performance of the slurry pump to be installed. This paper makes the comparison of some existing correlations available in the literature to predict the head reduction factors of such centrifugal pumps handling slurries. For this purpose, a large number of published data for various centrifugal slurry pump tests in the literature have been used to develop a new correlation and then this correlation and all others have been tested against the data. For the proposed correlation, the mean and average deviations between the calculated and measured head reduction factor is 8.378 and 0.620%, respectively, for all data of mostly handling commercial slurries. It also produces 12.441% mean deviation in the prediction of efficiency ratio for 216 data points. Overall, the new correlation that can be applied to both metal and rubber lined pumps with impeller diameter up to 850 mm, gives remarkably closer fit to the published data of both head and efficiency ratios than all existing correlations.

Effect of Wall Roughness on Laminar Flow of Bingham Plastic Fluids through Microtubes

Miniaturization of traditional devices is in high demand formicro-electro-mechanical systems~MEMS!. Examples includebut are not limited to optics, communication and information sys-tems, fluidics, biotechnology, medicine, automotive, and aero-space. An area of interest in several engineering fields is the con-trol of fluid flow within microchannels and microtubes. Theapplications include, but are not limited to, fields such as vibrationcontrol of structures and systems using small devices, reactors formodification and separation of biological cells, energy systems asa mobile power supply, heat exchangers for micro and macro de-vices, and propulsion engines @1–3#.In recent years, there has been growing attention given to theliquid flow in microchannels in parallel with the development ofminiaturized devices and systems. The understanding of flowcharacteristics, such as velocity distribution and pressure loss isnecessary in design and process control of microfluidic devices.Peng, Peterson, and Wang @4# experimentally studied the flowcharacteristics of water flowing through rectangular microchan-nels having hydraulic diameters of 0.133 to 0.367 mm and heightto width ratios of 0.333 to 1. Their results indicated that the lami-nar flow transition occurred for the range of the Re number be-tween 200 and 700. They also claimed that friction behavior forboth laminar and turbulent flow depart from classical thermofluidcorrelations, and the friction factor is proportional to Re

Optimal Magnetorheological Damper Configuration Using the Taguchi Experimental Design Method

Magnetorheological (MR) dampers have attracted the interest of suspension designers and researchers because of their variable damping feature, mechanical simplicity, robustness, low power consumption and fast response. This study deals with the optimal configuration of an MR damper using the Taguchi experimental design approach. The optimal solutions of the MR damper are evaluated for the maximum dynamic range and the maximum damper force separately. The MR dampers are constrained in a cylindrical container defined by radius and height. The optimal damper configurations obtained from this study are fabricated and tested for verification. The verification tests show that the dampers provide the specified damper force and dynamic range.

Prediction of Centrifugal Slurry Pump Head Reduction: An Artificial Neural Networks Approach

The feasibility of using artificial neural networks (ANN) in the prediction of head reduction of centrifugal pumps handling slurries is examined. An ANN model is proposed and compared with the empirical correlation given by the present authors earlier The comparison showed that the ANN could successfully be used for the prediction of head reductions of centrifugal slurry pumps. The mean deviation between predicted and experimental values is 5.86% which is reasonable for slurry handling processes.

Geometrical optimisation of vehicle shock dampers with magnetorheological fluid

Magnetorheological (MR) dampers have attracted interest from suspension designers and researchers because of their variable damping feature, mechanical simplicity, robustness, low power consumption and fast response. Therefore, optimisation of such devices is of particular interest to achieve optimal vibration control. This study deals with the geometrical optimisation of an MR shock damper using Taguchi experimental design approach. The optimal solutions of the MR damper were evaluated using analytical equations, which give the dynamic range of the damper under consideration. Optimal geometrical values obtained provided most performance in consideration of other nine alternatives of Taguchi experimental design specified for the study.

Dynamic characterisation of a vehicle magnetorheological shock absorber

Magnetorheological (MR) dampers have received remarkable attention due to being a potential technology to conduct semi-active control in mechanical systems in order to effectively suppress vibration. It is therefore important to understand the dynamic behaviour of such devices whose non-linear hysteresis is a complicated phenomenon. In the study, an MR damper has been designed, fabricated, tested and then its dynamic behaviour has been modelled with the classical Bouc-Wen hysteretic model. After that, the seven parameters of this model have been expressed in terms of only current excitation. By this, the total damping force has been given by a compact form in which the only independent variable is the current excitation. Finally, the model has been verified with experimental data and a good agreement has been observed.

2 Kanatlı Radyal Tipteki Bir Çamur Pompası Çarkının Optimizasyonu ve Analizi

With FLUENT, which is Computational Fluid Dynamics (CFD) software, it becomes possible to define the performance of complicated flow in turbo machines like pumps and blowers. It is not only reduced costs but also saves time. This study is aimed to optimize a commercial slurry pump impeller. Therefore, four different types of impellers were designed with using various blade angles, blade length and splitter blade on the impeller, which is the most crucial component of the pump. As a result of analysis it was seen that every impeller affected on the pump performance at different flow rate.

The optimisation and analysis of a centrifugal slurry pump impeller with 2 blades

With FLUENT, which is Computational Fluid Dynamics (CFD) software, it becomes possible to define the performance of complicated flow in turbo machines like pumps and blowers. It is not only reduced costs but also saves time. This study is aimed to optimize a commercial slurry pump impeller. Therefore, four different types of impellers were designed with using various blade angles, blade length and splitter blade on the impeller, which is the most crucial component of the pump. As a result of analysis it was seen that every impeller affected on the pump performance at different flow rate.

Exergy analysis of laminar fluid flow in stainless steel microtubes

In the study, exergy analysis of steady laminar fluid flow in stainless steel microtubes with diameters between 103 ?m and 179 ?m were conducted in the adiabatic conditions experimentally. The exergy losses were obtained for deionised water flowing in rough microtubes with the surface relative roughness of 2?6%. Results indicated that the exergy loss was in a good agreement with the conventional theory and the increasing in relative roughness leads to increasing exergy loss. As Re increases, measured exergy losses were found to be significantly higher than that of the predicted values.