THE IMPACT OF SELECTED PARAMETERS ON PRESSURE DISTRIBUTION IN THE FACE THROTTLE OF A CENTRIFUGAL PUMP AUTOMATIC BALANCING DEVICE

Face throttles are a necessary functional element of non-contact face seals and automatic balancing devices of centrifugal pumps of different constructions. To calculate the hydrodynamic forces and moments acting on the rotor and fluid flow through the automatic balancing device, it is necessary to know the pressure distribution in the cylindrical and face throttle when considering all important factors which predetermine fluid flow. The face throttle surfaces are moving, which leads to unsteady fluid flow. The movement of the walls of the face throttle causes an additional circumferential and radial flow, which subsequently leads to the additional hydrodynamic pressure components. The paper analyses viscous incompressible fluid flow in the face throttle of an automatic balancing device taking into account the axial and angular displacements of throttle’s surfaces and the inertia component of the fluid. The effect of local hydraulic losses as well as random changes in the coefficients of local hydraulic resistance at the inlet and outlet of the throttle is analysed.

Automatic Measurement System of High Resistance up to100TΩ

To solve the problems exist in the measurements high resistances in range of 1 MΩ~100 TΩ, such as low precision, poor repeatability, long time consuming and easy to be affected by the external environment, an adapted Wheatstone bridge for high resistances is described. The system uses two DC voltage sources to build a standard proportion, a pico-ammeter as the Null-indicator. The automatic balancing of the bridge is realized through the balance algorithm. The measurement software is compiled to realize the automatic measurement of high resistance. The shielding system is studied, the methods to improve the accuracy are summarized. The experimental results show that the standard uncertainty at 100GΩ reaches 3.2×10−5. The system can meet the calibration requirements of high value resistance, and has been applied in practical work.

Estimation of the influence of hydraulic balancing of the heating system and shading of external enclosures on the energy consumption of the university building

The main design features of single-pipe systems with vertical wiring, the reasons for their low efficiency, which include: physical and moral obsolete equipment and pipeline valves, lack of automatic control and regulation of coolant supply, low efficiency of heating devices, are characterized. Using the methodology according to DSTU B V.2.6-189-2013 and DSTU B A.2.2-12: 2015, the effectiveness of the introduction of automatic balancing of the heating system was first investigated, and then the effect of shading of external enclosing structures on the energy consumption of the university building, taking into account the existing state of external enclosing structures ... It has been established that balancing the heating system makes it possible to reduce the specific energy consumption for heating by 7.6%, and to reduce the energy consumption of the heating system by 164.8 MWh. The influence of the shading of external enclosing structures on the energy consumption of the building of the university is estimated, taking into account the existing state of the external enclosing structures in the absence of balancing the heating system of the building. It is shown that it leads to an insignificant excess of energy consumption for heating by 0.3 % or 6.6 MWh. It has been proven that the energy consumption of a building, taking into account the shading coefficient after balancing the heating system, can reduce the specific energy consumption for heating by 7.9 %, and reduce the energy consumption of the heating system by 165.4 MWh. Assessing the effect of shading of external enclosing structures "before" and "after" balancing the heating system of the university building, it can be argued that the energy consumption of the heating system has been reduced by 158.8 MWh or by 7.7 %. Key words: flow, balancing, solar insolation, heating system, shading

Research on High-Precision Attitude Control of Joint Actuator of Three-Axis Air-Bearing Test Bed

Three-axis air-bearing test bed is important semiphysical simulation equipment for spacecraft, which can simulate spacecraft attitude control, rendezvous, and docking with high confidence. When the three-axis air-bearing table is maneuvering at a large angle, if it is only controlled by the flywheel, it will cause the problems of slow maneuvering speed and high energy consumption, and when the external interference torque becomes large, the control accuracy will decline. A combined actuator including flywheel, air-conditioner thruster, and automatic balancing device is designed, and a hierarchical saturation PD control algorithm is proposed to improve the control accuracy and anti-interference ability of the three-axis air-bearing test bed. Finally, the mathematical simulation of the proposed control algorithm is carried out, and the physical verification is carried out on the three-axis air-bearing test bed. The results show that the control algorithm has higher control accuracy than the traditional control algorithm, and the control accuracy is better than 0.1 ∘ and basically meets the attitude control requirements of the ground simulation in-orbit satellite.

Computational Load Balancing Method for Hybrid Computing Systems

The paper considers the issues of the computations distributing within one node of a hybrid computing system for applied programs with computation-intense operations. A method is proposed for static distribution of computations, as well as a method for automatic balancing of the computational load during program execution, which is based on periodic analyzing the CPU load by the executed program and making decision to redistribute computational load if necessary. The proposed methods are implemented in an applied program that solves a gas dynamic problem using the computing resources of the multicore central processor and graphics accelerators. The results of program execution with various data distributions were obtained and analyzed, both with and without the mechanism for automatic balancing of the computational load.

A Smart Contract-Based P2P Energy Trading System with Dynamic Pricing on Ethereum Blockchain

We implement a peer-to-peer (P2P) energy trading system between prosumers and consumers using a smart contract on Ethereum blockchain. The smart contract resides on a blockchain shared by participants and hence guarantees exact execution of trade and keeps immutable transaction records. It removes high cost and overheads needed against hacking or tampering in traditional server-based P2P energy trade systems. The salient features of our implementation include: 1. Dynamic pricing for automatic balancing of total supply and total demand within a microgrid, 2. prevention of double sale, 3. automatic and autonomous operation, 4. experiment on a testbed (Node.js and web3.js API to access Ethereum Virtual Machine on Raspberry Pis with MATLAB interface), and 5. simulation via personas (virtual consumers and prosumers generated from benchmark). Detailed description of our implementation is provided along with state diagrams and core procedures.

Passive Balancing of the Rotor with an Auto-Balancing Device with a Viscous Incompressible Liquid

The use of liquid auto-balancers to compensate the operational changes in the imbalance of rotary systems without stopping them is of interest because of the relative structural simplicity of these devices, which are passive direct-acting regulators that do not require power supply and control systems to move correction masses. The experience of the study of passive auto-balancing devices (SBD) indicates that the existing theory (statements) of passive automatic balancing of the fluid is idealized and inaccurately describes the processes that occur with the working bodies during their operation. In particular, the lack of studies on the effect of liquid viscosity on the efficiency of self-balancing and the reasonableness of the selection of liquid during the development of fluid SBD demanded to analyse the operation of liquid SBD in the real system, taking into account the influence of liquid properties on the efficiency of the vertical rotor balancing process. It is shown that the efficiency of balancing increases with the approach of the angular velocity to the critical one and with the increase of the external resistance. The massive forces of the working fluid have less effect on the balancing efficiency than the viscosity for liquid SBDs.