Analysis of Rotor-Stator Interaction of a Pump-Turbine with Splitter Blades in a Pump Mode

The pump-turbine is the core component of a pumped storage power station. This paper considers an in-depth analysis of the rotor-stator interaction characteristics under computational fluid dynamics (CFD) and experimental measurements of pump-turbine with splitter blades used in a domestic pumped storage power station. The results show that as the guide blade opening increases, the rotor-stator interaction of the pump-turbine intensifies and the magnitude of the runner radial force and its pulsation amplitude as well as the magnitude of the guide blade water moment and its pulsation amplitude also increase. In addition, when the opening degree increases from 9.8° to 17.5°, the influence on the main frequency is mainly reflected in the phase change. While the opening degree increases from 17.5° to 24.8°, the influence on the main frequency is mainly reflected in the amplitude change. Moreover, the amplitude of 5fn at opening 9.8° and opening 24.8° is greater than the optimal opening 17.5°, indicating that deviation from the optimal opening will aggravate the difference of rotor-stator interaction between splitter blades and guide blades. In the paper, the influence of guide blade openings on the rotor-stator interaction between the splitter guide blade is studied, which provides a theoretical reference for the stable operation of the pump-turbine.

The Effect of Using the Flow Separator Blade to Increase the Uniformity of Flow in the Intake Manifold

ABSTRACTIn this paper, an idea to make the flow uniform inside the manifolds of four and six cylinder engines without changing their main geometries is presented. In general the uniform distribution of air flow among the engine cylinders is very important. Non-uniform flow in the intake manifold outlets causes inadequate feeding of the cylinders, inappropriate combustion and reduces engine volumetric efficiency. So this matter is vital for improving engine performance. A flow guide blade is added into the manifold and uniformity of the air flow is studied in different regime using transient numerical simulations. The amount of air exited from each outlet and the effect of this blade on flow uniformity is investigated. The results showed that the blade has made the flow more uniform in the manifold outlets and it was also found that in the four-cylinder and six-cylinder engines the flow uniformity is increased by 67% and 75%, respectively. In other words, as the number of engine cylinders increase, the effect of using this blade increases.

KAJI EKSPERIMENTAL PENGARUH BAFFLE PADA ALAT PENUKAR PANAS ALIRAN SEARAH DALAM UPAYA OPTIMASI SISTEM PENGERING

Heat exchangers or heat exchangers are tools used to change the temperature of the fluid or change the fluid phase by exchanging heat with another fluid. In a heat exchanger, the ability to exchange heat is largely determined by the type of fluid flow and fluid passing through the heat exchanger. The use of heat exchangers in the field of drying is now a necessity to overcome the problems of drying productivity. The purpose of this study was carried out to determine the effectiveness of the heat exchanger experimentally based on directional flow by comparing construction using baffle and without using baffle in an effort to optimize the drying system. The research method was carried out by fabricating 2 units of heat exchangers and by field testing. The test data obtained are the input and output temperatures of the heating fluid flow and cooling fluid flow and flow velocity. Based on preliminary research data shows that the use of baffle affects the increase in temperature on the heat exchanger, where at the fresh air outlet that does not use baffle produces a temperature of 72oC while the baffle produces 88oC with the Log Mean Temperature Difference heat exchanger without using a baffle higher than heat exchanger that uses a baffle guide blade. This can illustrate that the smaller heat losses are wasted so that the absorption of heat by the reverse system will be higher.

Computational analysis of a cross flow turbine performance

In the electrical energy generation context in Colombia, the water resources represent the 64% of the potential generated according to UPME in the 2015 year; becoming into a solution to the growing energy demand and to the supply of energy in non-interconnected zones. The cross-flow turbines as Michell-Banki type, become an efficient and economically attractive choice. This paper shows the fluiddynamic performance of a laboratory’s model turbine under several operating conditions. The development of this analysis is supported by the results of experimental tests, uses the computational fluid dynamics as a tool for modelling, estimate, and analyse the turbine behaviour under different operating conditions, with ANSYS-Fluent software; the computational model considers the most important geometric aspects of the turbine and the opening percentage effect of the guide blade. The water flow through the rotor is approach through a turbulence model as κ – ε type. The numerical study results agree satisfactorily with the turbine performance observed in the laboratory.

Performance influence in submersible pump with different diffuser inlet widths

The diffuser inlet width is a key geometric parameter that affects submersible pump performance. On the basis of diffuser characteristic curve analyses, diffusers with different inlet widths and the same impeller were equipped to construct a submersible pump model through the use of AutoCAD software. The performance curves of the submersible pump, with six diffuser inlet widths, were obtained using computational fluid dynamics method. Simultaneously, the simulation results were tested with the experimental method presented in this article. The results show that the optimum value of the inlet width ( b3 = 50 mm) is larger than the experience-based one. With an increase in the inlet width, the optimum operating point of a submersible pump offsets to a larger flow rate. When the guide blade inlet width is approximately 40–55 mm, the submersible pump efficiency is relatively high, approximately 75.9%–83.7% capacity, and the flow rate is approximately 105–135 m3/h. The numerical results of submersible pump performance are higher than those of the test results; however, their change trends have an acceptable agreement with each other. The practical significance is supplied by changing the inlet width of the diffuser to expand the scope of use.