Numerical Simulation of Centrifugal Pump and Effect of Impeller Geometry on Its Performance
Mohamed Hassan Gobran,
Mostafa Mohamed Ibrahim,
Ramy Elsayed Shaltout,
Mahmoud Ahmed Shalaby
Issue:
Volume 4, Issue 2, April 2019
Pages:
21-29
Received:
2 April 2019
Accepted:
15 May 2019
Published:
4 June 2019
Abstract: In the presented paper, the effect of impeller geometric parameters on the performance of centrifugal pump has been investigated. This study was performed for different flow rates and rotational speeds, allowing to obtain the performance curve for the centrifugal pump. Three dimensional computational fluid dynamic simulation of the impeller and volute for a centrifugal pump has been performed using ANSYS CFX software (a high-performance computational fluid dynamics software tool that delivers reliable and accurate solutions). The pump has an outside impeller diameter of 205 mm, impeller outlet width of 16 mm, rotational speed 1450 rpm, seven impeller blade and a specific speed of 28. By increasing the impeller outer diameter and outlet width, both net head and power consumed are increased. In addition, it was noticed that the best efficiency point (BEP) was achieved at volume flow rate higher than design flow rate. The performed simulations indicated that; by changing the impeller outer diameter from 200 mm to 210 mm, the flow rate of BEP increases about by 14.7%. By changing the impeller outlet width from 14 mm to 18 mm, the flow rate of BEP increased by about 9%, and the efficiency of BEP reduced by approximately 0.5%. It was also noticed that, increasing the rotational speed will cause an increase in the net head and consumed power. An increase of 13.8% for the flow rate of BEP was observed when changing the rotational speed from 1400 rpm to 1500 rpm, with the same BEP.
Abstract: In the presented paper, the effect of impeller geometric parameters on the performance of centrifugal pump has been investigated. This study was performed for different flow rates and rotational speeds, allowing to obtain the performance curve for the centrifugal pump. Three dimensional computational fluid dynamic simulation of the impeller and vol...
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Economic Life Cycle versus Lifespan – A Case Study of an Urban Bus Fleet
Hugo Raposo,
José Torres Farinha,
Inácio Fonseca,
Diego Galar
Issue:
Volume 4, Issue 2, April 2019
Pages:
30-43
Received:
17 October 2018
Accepted:
7 November 2018
Published:
10 June 2019
Abstract: The maintenance policy and the quality of service throughout the bus’s life cycle can be measured through their costs along time that, when evaluated using Lifespan or Economic Life Cycle methods, allow to determine the renewal or the replacement time. The paper discusses these two models, using real data from an urban bus fleet company. The maths that supports the models are presented. They are considered the functioning and maintenance costs, and also the apparent rate. The Life Cycle Cost of an urban transport bus is strongly dependent on the policy and quality of its maintenance, from which it depends on its reliability and availability. The final result is reflected on its Life Cycle Cost, that can be evaluated through the Lifespan or the Economic Life Cycle methods. Other aspects that can be considered are the fuel costs and the type of terrain, because they are intrinsically interrelated and have a strong effect on costs, namely because they imply strong variation in the bus’s consumption and in their maintenance costs. As the company considered in the case study has a poor maintenance policy, it makes the analysis challenging, making difficult to compare the economic life cycle with the lifespan method in this situation. However, the results and conclusions that are taken from them are obvious, what demonstrates the models’ utility and robustness.
Abstract: The maintenance policy and the quality of service throughout the bus’s life cycle can be measured through their costs along time that, when evaluated using Lifespan or Economic Life Cycle methods, allow to determine the renewal or the replacement time. The paper discusses these two models, using real data from an urban bus fleet company. The maths ...
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Integration and Evaluation of the Impact of Distributed Generation on the Protection System of Distribution Network with DG Using Etap
Modu Abba Gana,
Usman Otaru Aliyu,
Ganiyu Ayinde Bakare
Issue:
Volume 4, Issue 2, April 2019
Pages:
44-51
Received:
28 February 2019
Accepted:
9 May 2019
Published:
12 June 2019
Abstract: Distributed Generation (DG) has been growing rapidly in deregulated power systems due to their potential solutions to meeting localized demands at distribution level and to mitigate limited transmission capacities from centralized power stations. Penetration of DG into an existing distribution system has so many impacts on the system. Despite the benefits a DG will provide; it has a negative impact on the power system protection, thus affecting both reliability and stability of the system. This paper evaluates the impact of DG on the power protection systems with DG integrated in the systems. IEEE 33 Bus system was modelled in full operational details using ETAP. Protection coordination was carried out using Modified PSO. To investigate the impact of DG on the protection systems, different fault scenario have been simulated with and without DG installed. The fault current level, false tripping, unintentional islanding, and behavior of the existing protection system were investigated considering two scenarios. Case one was the integration of single DG while case two was the integration of two DGs. The type of DG integrated was solar photovoltaic. Simulation results revealed that the fault current level for a 3 phase fault at bus 27 for the system increases by 2.5% for case one and 24% for case two. There was unitentational islanding and false tripping as a result of the current contribution from the DG. The sequence of operation of the protective devices clearly showed that there was mis coordination of the protective devices.
Abstract: Distributed Generation (DG) has been growing rapidly in deregulated power systems due to their potential solutions to meeting localized demands at distribution level and to mitigate limited transmission capacities from centralized power stations. Penetration of DG into an existing distribution system has so many impacts on the system. Despite the b...
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