As one of the core components of the fire-fighting water-supply system, the performance of a fire pump directly determines the extent of damage caused by the fire. Compared with conventional pumps, the design requirements of fire pumps not only need to ensure that the head of the pump is at 0Qd, 1. 0Qd, and 1. 5Qd and its efficiency is at 1. 0Qd but also consider the cavitation performance at each flow rate, which presents a greater challenge for the design of high-performance fire pumps. By optimizing the design of a centrifugal fire pump with a specific speed of 24. 7, numerical calculations were performed to obtain the best optimized scheme Y4. The results show that at the design flow rate the best optimized scheme improves the efficiency by 9. 17% compared with the original scheme, and the head meets the design requirements of the fire pump while avoiding the hump phenomenon. Through a comparative analysis, it was found that the optimized scheme Y4 can reduce the pressure pulsations at the outlet of the pump and improve the cavitation performance at each flow rate. The experiment verifies that the head of the best optimized scheme at the design flow rate is 74. 43m, the pump efficiency is 40. 22%, and there is no hump in the head curve, which can meet the design and use requirements of the fire pump. The maximum reduction in the outlet pressure pulsations coefficient in the best optimized scheme was 47. 12% on average. Compared with the original scheme, the critical net positive suction head (NPSHr) of the best optimized scheme was reduced by 21. 5%, 17. 6%, 15. 7%, and 16. 8%, respectively.

In this research, the sensitivity analysis is applied to an electroHYDRAULIC servovalve which is a nonlinear system. This system sensitivity study differs from previous studies by considering the dynamic behaviour and nonlinearity of the system performance. Different sensitivity analysis methods are compared to each other by studying the sensitivity of the actuator piston velocity of above servovalve with respect to eighteen parameters. By using the best method among the above mentioned methods, the sensitivity of the state variables of the sample system have been studied.

The analysis of flow in water-distribution networks with several pumps by the Content Model may be turned into a non-convex optimization uncertain problem with multiple solutions. Newton-based methods such as GGA are not able to capture a global optimum in these situations. On the other hand, evolutionary methods designed to use the population of individuals may find a global solution even for such an uncertain problem. In the present paper, the Content Model is minimized using the particle-swarm optimization (PSO) technique. This is a population-based iterative evolutionary algorithm, applied for non-linear and non-convex optimization problems. The penalty-function method is used to convert the constrained problem into an unconstrained one. Both the PSO and GGA algorithms are applied to analyse two sample examples. It is revealed that while GGA demonstrates better performance in convex problems, PSO is more successful in non-convex networks. By increasing the penalty-function coefficient the accuracy of the solution may be improved considerably.

One of the basic principles of any organization is to assure about obtained figures of its products MEASUREMENT. If the measured data is not trusted, the possibility of wrong decisions regarding the approval or rejection of products and obviously the cost would be great. First cases in MEASUREMENT SYSTEMS analyses which cross minds are criteria for approval or rejection for any MEASUREMENT system use its obtained results. It seems that comparing and ranking different MEASUREMENT SYSTEMS have an important role in future of any organization, when every system is evaluated by common criteria in MEASUREMENT SYSTEMS analysis. MCDM methods can greatly influence decision quality. Although, some limitations has been seen in the description of criteria or sub-criteria information in classical VIKOR under linguistic environment, which result in the loss and low rate of accuracy of information. Therefore, to solve that problem VIKOR method has been developed by many researchers. In this paper, the rank of different MEASUREMENT SYSTEMS as an alternative, average attribute and calculated index is considered as a benchmark in MEASUREMENT SYSTEMS analysis. For this purpose, a multiple criteria decision-making model of VIKOR method has been presented. In order to determine the Attribute weight, an AHP method has also been used before VIKOR. In order to fully consider the relative importance of the criteria, and create a balance between total and individual satisfaction the VIKOR method is applied to aggregate the whole criteria. The extended VIKOR can rank and select the best one from a set of alternatives.