The Flow-Heat Coupling Study of Cooling Circulating Channel of Magnetic Drive Pump

The medium in the cooling circulation channel of the magnetic drive centrifugal pump will take away the heat generated by the magnetic eddy current and bearing friction in time to avoid the high temperature demagnetization phenomenon of the permanent magnets. Therefore, the reasonable design of the cooling circulation channel directly affects the stable operation of the magnetic drive centrifugal pump. In this paper, the heat exchange and temperature distribution in the cooling circulating channel of magnetic drive pump are studied by means of numerical calculation of fluid-heat coupling and external characteristic test. The temperature distribution and development law of the isolation sleeve clearance, the bottom of the isolation sleeve and the reflow hole are analysed emphatically, and the convection heat transfer coefficient distribution in the isolation sleeve clearance is studied.

Компактный аппаратно-программный комплекс для диагностики электронных регуляторов САУ ГТД в эксплуатации

The relevance of creating a compact hardware and software complex is analyzed to ensure a full check of the operability of electronic regulators of gas turbine engines, in particular, the AI-35 engine, developed by SE "Ivchenko-Progress". The article describes the composition and functionality of the device developed by Element JSC, which was named “Complex of software and hardware for imitation of actuators and engine sensors”. The complex under consideration is intended both for autonomous use and for work as part of an automated workstation (AWS), which in turn is a part of the AI-35 engine semi-natural simulation stand. A feature of the complex is that it contains built-in mathematical models of the engine, electric drive pump-fuel regulator, as well as sensors installed on the engine. Based on the results of processing digital signals from an automated workstation or a touchscreen display, the complex generates output analog and frequency signals – rotor speed, pressure at the compressor outlet, the temperature at the compressor inlet, temperature of gases at the outlet of the turbine. The complex also generates control signals for the imitation of igniting pyro plugs and a fuel pyrovalve, in particular, it provides an imitation of their "combustion" by breaking the circuit. The built-in touchscreen display makes it easy for the operator conducting the governor and engine tests to use the complex as intended. With the help of the display, without using a PC, the operator can manually control the process of simulating the issuance of a command to start the engine by changing the values of the rotor speed, form various modes of engine operation, setting the appropriate parameters, simulate engine surge, etc. The functionality of the developed complex provides debugging of GTE control algorithms and subsequent tests of the regulator.

CFD Analysis on the Balancing Hole Design for Magnetic Drive Centrifugal Pumps

Balancing holes in single-suction centrifugal pumps are generally applied to attenuate the axial thrust caused by a pressure difference between the front side of a shroud and the rear side of a hub of an impeller. The magnetic drive pump, the subject of this study, has a leak-free airtight structure and an integrated structure of the impeller and inner magnet. To prevent the performance degradation of the magnetic drive caused by heat during operation, complex cooling flow paths connected to balancing holes have been designed so that a sufficient amount of coolant would flow around the magnetic drive. Due to this spatial characteristic, when balancing holes are applied to a magnetic drive pump, the balancing hole flow path becomes very long compared to that of balancing holes applied to conventional pumps. When the balancing hole flow path is long, the flow path loss increases, which in turn increases the adverse effect of balancing holes on the pump performance. Therefore, the design of highly efficient balancing holes to which a sufficient amount of coolant can be supplied is critical in a magnetic drive pump. To this end, two types of balancing holes were investigated in this study. First, balancing holes are drilled in the impeller that rotates during operation. Second, balancing holes are drilled in the inner shaft installed to maintain the centre of rotation of the impeller during pump operation. The results confirmed the flow characteristics of the two types of balancing holes and verified the effect of each balancing hole on the pump performance. Finally, this study found that drilling balancing holes in the shaft were appropriate for the magnetic drive pump, and this type can maintain relatively high efficiency and supply a sufficient amount of coolant to maintain the efficiency of the magnetic drive.

Optimization Design of the Impeller Based on Orthogonal Test in an Ultra-Low Specific Speed Magnetic Drive Pump

To improve the hydraulic performance in an ultra-low specific speed magnetic drive pump, optimized design of impeller based on orthogonal test was carried out. Blades number Z, bias angle in peripheral direction of splitter blades θs, inlet diameter of splitter blades Dsi, and deflection angle of splitter blades α were selected as the main factors in orthogonal test. The credibility of the numerical simulation was verified by prototype experiments. Two optimized impellers were designed through the analysis of orthogonal test data. The internal flow field, pressure fluctuation, and radial force were analyzed and compared between optimized impellers and original impeller. The results reveal that impeller 7 (Z = 5, θs = 0.4θ, Dsi = 0.75D2, α = 0°) could increase the head and efficiency, compared to the original impeller, by 2.68% and 4.82%, respectively. Impeller 10 (Z = 5, θs = 0.4θ, Dsi = 0.55D2, α = 0°) reduced the head by 0.33% and increased the efficiency by 8.24%. At design flow rate condition, the internal flow of impeller 10 was the most stable. Peak-to-peak values of pressure fluctuation at the volute tongues of impeller 7 and impeller 10 were smaller than those of the original impeller at different flow rate conditions (0.6 Qd, 1.0 Qd and 1.5 Qd). Radial force distribution of impeller 10 was the most uniform, and the radial force variance of impeller 10 was the smallest.