Rolling Rotor Research Articles

Simulation analysis of flow and acoustic characteristics of exhaust muffler of rolling rotor compressor

Simulation analysis of flow and acoustic characteristics of exhaust muffler of rolling rotor compressor

Выбор способа снижения трения в разрабатываемых для импортозамещения ротационных холодильных компрессорах

The article discusses one of the methods for reducing friction, used for newly developed rotary compressors as part of import substitution work. The experience of using rotary refrigeration compressors is analyzed and the main factors determining refrigeration capacity are identified. Methods used in aerospace engineering and power engineering to reduce friction and increase the service life of mechanical elements and assemblies using metallic and non-metallic materials have been identified, and the most promising materials and development trends have been analyzed. A fairly common method of reducing friction, based on the weariness effect, is chosen for study. Based on already known results, a technical solution based on the wear-free effect has been proposed to reduce friction of a refrigeration compressor with a rolling rotor.

Zero-Pole Cancellation Based Iterative Learning Control Method for Speed Ripple Suppression of Single Rolling Rotor Compressor

Zero-Pole Cancellation Based Iterative Learning Control Method for Speed Ripple Suppression of Single Rolling Rotor Compressor

Bending and torsional coupling study of rolling-piston compressor valves

In this paper, a model of a rolling compressor valve with one end fixed horizontally is presented and simulated using the flow-solid coupling (FSI) method for rolling rotor type compressors. Optimisation of the diagonally cut section can effectively reduce the pressure pulsation of the compressor. The results show that the valve blade generates coupled vibrations of bending and torsion, and the slant-cut structure improves the frequency of pressure pulsations, increases the stability of the compressor valve blade, optimises the compressor structure and reduces the pressure pulsations of the compressor.

Sound insulation prediction and band gap characteristics of four vibrators acoustic metamaterial with composite phononic crystal structure

Acoustic Metamaterial have been widely concerned because of their strong sound insulation characteristics for specific low-frequency bands. However, further optimization is still needed in terms of broadband sound insulation characteristics, and phononic crystals can generate multiple sound insulation bandwidths due to their unique bandgap characteristics. Therefore, a four vibrators acoustic Metamaterial structure with phononic crystals is proposed to broaden the sound insulation performance at medium and high frequencies while retaining the advantages of sound insulation at low frequencies. Firstly, a semi analytical method combining finite element analysis was proposed for the sound insulation performance of the structure. Afterwards, a bandgap theory based on the equivalent medium method was proposed to reveal the reasons for its characteristics. Finally, a cylindrical sleeve structure was designed for a certain rolling rotor compressor, and its sound insulation performance in the cylindrical state was verified through finite element simulation.

Dynamics Analysis of a Rolling Rotor Compressor Considering the Electromagnetic Force

Rolling rotor compressor is a commonly used compressor in air conditioning systems, and studying its internal dynamic characteristics plays an important role in the vibration and noise of air conditioning systems. Due to the integration of the motor rotor and shaft inside the compressor, the influence of electromagnetic force needs to be considered when analyzing the dynamics of the compressor. This paper studies the rotor dynamics characteristics of a rolling rotor compressor, considering not only the bearing force and gas force inside the cylinder, but also the electromagnetic force of the motor rotor. Firstly, the gas force, electromagnetic force, and bearing force on the compressor shaft are analyzed; Secondly, a two degree of freedom rotor bearing dynamic model of the compressor shaft is established, and the dynamic characteristics of the shaft are obtained by solving the model though the Runge-Kutta method; Finally, the vibration characteristics of the compressor shaft are analyzed in both the time and frequency domains. The results indicate that the influence of electromagnetic force cannot be ignored, and the coupling effect between electromagnetic force and bearing force can be seen.

Simulation of refrigerant-lubricant two-phase flow characteristics and performance test in space compressor

The vapor-compression heat pump allows for lightweight heat-control systems and efficient heat emissions. It is considered to be the best choice for future space thermal control systems. To solve the problem of separation and compression deterioration of conventional positive-displacement refrigeration compressors in a microgravity environment, an innovative microgravity solution, mixing refrigerant and lubricant without oil separation, is proposed. A flow model in the compression chamber was developed and simulations were performed to investigate the effects of gravity and lubricant volume fraction on the flow characteristics of the refrigerant-oil mixture in a rolling rotor compressor. A modified compressor performance test bench was built and the effect of compressor speed on parameters such as power and heat dissipation was investigated experimentally. The results showed a maximum difference between the simulated and experimental values of compressor discharge temperatures of 9.16 %. Under microgravity conditions, a lubricant-refrigerant mixture with a volume fraction of less than 5 % can serve as the system working medium. The lubricant volume fraction at the outlet of a compressor cycle in normal gravity was 4.9 %, while it was 3.34 % in microgravity. As the compressor speed increased from 1500 to 5000 rpm, the compressor power increased from 15.5 to 64.5 W and the system heat discharge rate increased from 115.2 to 164.1 W. The system refrigeration coefficient of performance (COPc) decreased from 6.4 to 1.5, while that of heat dissipation, COPh, decreased from 7.4 to 2.5.

Dynamic Characteristic Analysis of Permanent Magnet Brushless DC Motor System with Rolling Rotor

With the wide application of permanent magnet brushless DC motors (BLDCMs) in home appliances and electric vehicles, there is increasing demand for BLDCMs with low vibration and noise. This paper aims to study the dynamic characteristics of a type of BLDCM with a rolling rotor. Firstly, a dynamic model of a BLDCM with eighteen degrees of freedom (18 DOFs) is built, for which the electromagnetic force and the oil-film force of the sliding bearing are considered. Then, the system responses are solved by Runge–Kutta numerical method, and the effects of the rotational speed, bearing backlash and eccentric distance of the rolling rotor on the dynamic response are analyzed in detail. The time history, frequency plot, axis trajectory diagram and phase portrait are introduced to discuss the dynamic behavior of the motor system. Analysis results show that eccentric force increases obviously with increasing rotational speed or eccentric distance, which can change the dynamic response through suppressing the electromagnetic force. The effect of bearing clearance on the rotor and stator is negatively correlated. Therefore, system parameters should be determined properly to improve the running performance of the motor system. Numerical results can provide a useful guide for the design and vibration control of such motor systems.

Analysis of electromagnetic characteristic in the interior permanent magnet brushless DC motor

The motor vibration is mainly induced by the electromagnetic excitation. In order to improve the running performance of the permanent magnet brushless DC motor (BLDCM) within the rolling rotor compressor, this paper builds the predicted model of the electromagnetic excitation and analyzes the electromagnetic characteristic of the BLDCM. Firstly, the electromagnetic field is divided into four regions in 2D plane, including the magnet, air gap, stator slot, and slot-opening subdomains. Then, the relative equations of the electromagnetic field are constructed, and the vector magnetic potential is solved by the variable separation method. Thus, the magnetic flux density of the air gap is derived by the corresponding vector magnetic potential, which is used to describe the electromagnetic excitation. Based on the built model, the effects of the slot opening and air gap length on the electromagnetic characteristic are analyzed. The analysis results can provide a reference for the improvement of the electromagnetic characteristic of the BLDCM by structure optimization.

SIMULATION OF TROLLEBUS STEERING SYSTEM WITH ELECTRIC POWER STEERING BASED ON ROLLING ROTOR SWITCHED RELUCTANCE MOTOR

The analysis of power steering which used on modern rolling stock is carried out. Their main shortcomings are identified. Given the requirements for the steering of trolleybuses, a solution to increase its efficiency is proposed. Based on the developed mathematical model and functional diagrams of the trolleybus steering system with a electric power steering based on rolling rotor switched reluctance motor, a simulation model of trolleybus steering was created using the Matlab Simulink package. The peculiarity of the simulation model is taking into account the mass and size characteristics of the rolling stock, the parameters of the suspension of the steered axle, the impact of the road surface and the speed of the trolleybus, changes in the parameters of the electric motor magnetic system during operation. The rolling rotor switched reluctance motor which is offered for use as the electric power steering of the LAZ E183D1 trolleybus is calculated. The calculation of the magnetic system of the engine by the finite element method with the subsequent approximation of the obtained results is carried out. With the help of the developed simulation model the simulation of the trolleybus steering system with electric power steering based on rolling rotor switched reluctance motor was performed. Time diagrams of transients in the trolleybus steering system are obtained and their processing and analysis are carried out.

Development of a mathematical model of the trolleybus steering system using a rolling rotor switched reluctance motor

An important part of the overall task of social and economic development of many developed countries is the creation of a unique transport infrastructure or improvement of transport services for the population.
 The cumulative solution to many problems is to improve the quality and reliability of elements and equipment in any vehicle design. This determines its efficient operation and the safety of passengers.
 A common urban electric transport in megacities is a trolleybus, the reliability of which depends on individual components and assemblies, power supply systems and traffic control.
 But this type of transport requires modern scientific and technical solutions for the design of individual components and assemblies, for example, steering, which is directly related to the safe and comfortable transportation of passengers.
 An innovative technical solution has been proposed that will increase the energy efficiency of the trolleybus steering system through the use of an electric power steering based on a rolling rotor electric motor. The analysis of the design is carried out and the principle of control of the rolling rotor motor is determined. Functional diagrams of the components of the trolleybus steering system with an electric power steering based on a rolling rotor motor are developed. The electromagnetic and mechanical connections of the motor with the rolling rotor are determined and mathematically described. Factors affecting the steering system when turning the steered wheels are reasoned. A mathematical model of a trolleybus steering system with an electric booster based on an electric rolling rotor motor has been developed. The mathematical model is based on the differential equations of the electrical and mechanical parts. Algebraic equations were used to characterize the electromagnetic connections of the rolling rotor motor. The proposed solution will allow simulating dynamic processes in the trolleybus steering system and evaluating the results. Determination of the efficiency of the steering system was carried out by comparative analysis of the following factors: the control action created by the driver, the condition of the road surface, dynamic and transient electromechanical processes of the system, and the like

Assessment of efficiency of electric drive of stop valves

The operation features of the stop valve electric drive are analyzed. It is found that the drive of stop valves, implemented on the basis of induction motors, is characterized by low energy efficiency. For the purposeful improvement of the energy efficiency of the electric drive, a method is developed for estimating the energy efficiency of the valve module. The need to develop the method is due to the fact that energy efficiency estimates based on international standards are valid for steady-state operating conditions, provided that the time of transient processes is neglected. Unlike traditional types of actuators, the stop valve actuator is characterized by low speeds. The use of mechanical gearboxes does not significantly reduce the drive speed, so you have to carry out pulse control of the engine or switch to a gearless drive. The efficiency of alternative engine types is estimated using the proposed method, which is based on valve positioning modeling. The trajectory of movement is formed in accordance with the control pulses applied to the windings of the motor, which is part of the mechatronic module. Testing of the method is carried out on the basis of the passport data of the 120 W AIR56A4 induction motor, which is part of a serial single-turn mechatronic module. For comparison of energy indicators, a 3-phase synchronous rolling rotor motor was chosen, whose parameters of the stator winding are similar to those of the AIR56A4 motor winding. Comparison of energy efficiency estimates showed the advantage and prospects of using gearless synchronous motors in the valve drive. The developed models allow to investigate and optimize the characteristics of the electric drive based on the tested engines, as well as to formulate the requirements for the engine design and technological parameters based on the obtained energy efficiency estimates. The proposed method of energy efficiency assessment is the basis for the implementation of a set of technical tools to assess the drive energy efficiency in real industrial conditions when performing a specific technological task.

High-torque low-speed electric motor with a rolling rotor, as an alternative to existing gear motors

Purpose. Getting the dependence of three-tooth motor with a rolling rotor (MRR) torque value from the active length of its rotor by the calculation of magnetic field distribution in four different construction of the MRR. Methodology. Modeling of electro-magnetic processes in ANSYS Maxwell 3D solution, which appeared in MRR with different type of construction and properties of its material. Results. The results of numerical and field calculation in the ANSYS Maxwell program of four design versions differing via the length of the rotor core active parts and the materials of the stator are presented. The distributions of the magnetic induction in the air gap were obtained, as well as the value of the torque for each MRR design. Also as a result we made the conclusions, that rotor with a half-length of the rotor has a best result of the torque value and less size of its main parts. Originality. MRR is a non-standard machine in which the rotor rolls over the stator surface with guaranteed eccentricity. Practical value. A 3D model of a high-torque low-speed MRR with an axial magnetic flux are presented, and the results of its modeling calculation and experimental researches are shown for various type of its construction with different size and material properties.

АНАЛІЗ ПРОБЛЕМ СИСТЕМИ РУЛЬОВОГО КЕРУВАННЯ ТРОЛЕЙБУСІВ ТА ПЕРСПЕКТИВИ ЇХ ВИРІШЕННЯ

Electric transport is a necessary part of infrastructure of large cities and is used for the transportation of passengers or cargo. Therefore, the issue of its constant updating or modernization and improvement of some elements is acute. The analysis of problems during the operation of trolleybuses was carried out and the object of modernization of steering control on the basis of the trolleybus brand LAZ-E183 was determined. The purpose of the work is to develop steering control of simplified design and increased energy efficiency. The object of research is design the amplifiers of the steering system of trolleybuses. The subject of the study is processes and characteristics that affect energy efficiency of steering systems. The scientific novelty is an innovative solution to increase the energy efficiency of the steering system of trolleybuses through the use of an electric motor with rolling rotor, which allows to realize a high torque unlike traditional electric motors. The practical value of a new technical solution is develop an electric power steering system of trolleybus through the use of an electric motor with rolling rotor, as well as in reducing the size and simplified design of the steering booster. The application of the engine with rolling rotor makes it possible to reduce the power consumption of the on-board network by switching on the electric power steering only at the moment of turning the trolley, which also increases the energy efficiency of the steering control.

IMPROVING THE RELIABILITY OF POWER TRANSFORMERS OLTC DEVICES

It is established that one of the effective ways to improve the reliability of the power transformer as a whole is to increase the reliability of its on-load tap-changer (OLTC). As a result of the analysis of statistical material obtained under real operating conditions (the number of transformers is 1000 pieces, the observation period is 4 years), the failure statistics of its individual elements are given. It is shown that the most not reliable elements of the OLTC are the drive and the contactor. To improve the reliability of the OLTC, the possibility of its development on the basis of an engine with a rolling rotor is considered. A critical analysis of modern OLTC and the proposed technical solution is carried out. The technical and economic feasibility of developing and implementing a new device has been established. On the basis of the general theory of the electromagnetic field, a technique and an algorithm for calculating new sizes of an engine with a rolling rotor for OLTC of power transformers has been developed. The analysis of operational reliability of OLTC based on statistical materials is carried out; the main reliability indices of its elements are calculated. It is established that the introduction of a new technical solution will increase the reliability of the OLTC by 25% and the power transformer by 2-4%. The perspective of the development of a new OLTC device is presented.

RESEARCH OF DYNAMIC PARAMETERS OF THE ELECTRIC DRIVE ON THE BASIS OF ROLLING ROTOR MOTOR

Purpose. Development and investigation of a dynamic model of electric drive on the base of the rolling rotor motor (RRM) which reflects the positioning of the actuator of the locking and regulating equipment in time. Methodology. Analytical description of electromagnetic and mechanical processes in the electric drive during the RRM shaft movement by using a system of differential equations. Numerical imitation modeling with the processes visualization in the Matlab environment of the RRM rotor displacement with mechanical load in time. Results. It is shown that the degree of influence of the value of the load inertia on the dynamics of the object obtained by the waveform changes the rotation angle of the rotor and motor speed in time. The degree of influence of the value of the electromagnetic time constant of the dynamics of the positioning of the actuator, and the nature of transients during acceleration and fixing position of the rotor with a predetermined moment of inertia for different values of inductance. The effect of the ratio of electromechanical and electromagnetic time constants of the nature of the transition processes accompanying jog mode angular displacement of the drive shaft on the base of RRM. Originality. The lack of technical means to ensure acceptable accuracy time measurement of angular displacement shaft of the actuator in jog mode offset by using a laser meter which gives the opportunity to assess the adequacy of the dynamic model of the RRM. Practical value. The results of investigations allow to create a tool for optimization of structural, technical and hardware and software solutions for the improvement and modernization of the projected electric locking and regulating equipment. The direction for improving the dynamics of the drive on the basis of RRM is indicated providing for an increase in its torque characteristics of the motor by reducing the influence of the parameters of transients.

Experimental Study on Integrated Solar System Freezer

Based on the 24V DC rolling rotor compressor having the advantages of structural simplicity, light weight, small clearance volume, high exhausting coefficient, we design and build a solar photostatic DC refrigerator with an effective volume of 53 liters. We integrate solar photostatic panels with the refrigerated cabinet, and use solar power collection system and Agilent 34970A data acquisition instrument to collect voltage, current, electric quantity and temperature of integrated solar refrigeration system components. Experimental results show that: the integrated solar refrigerators operate reliably in Harbin. The two solar panels placed on the top of the box respectively stick attached to the sidewalls of the box and tilted at 48 degrees towards south, each with the maximum daily power generation 0.45kW.h. No-load and full-load running of the compressor running rate are 21.1%(24h) and 18.6%(24h), and the average power consumption respectively is 56.6W and 61.2W, the daily electrical power consumption is 0.29kW.h and 0.27kW.h. The generating capacity can meet the normal demand of the compressor for five consecutive rainy days. It means the various components can match reasonably. The study provides reference valuable to the integrated solar refrigerators commercialization.

FEM Analysis of a New Electromechanical Converter with Rolling Rotor and Axial Air-Gap

The paper presents the modeling of a new type of electromechanical converter with rolling rotor (ECRR) in order to obtain an optimisation at functional level. The ECRR prototype compri ...

The maximum dynamic eccentricity ratio of hydrodynamic rolling hybrid bearings

Hydrodynamic Rolling Hybrid Bearing (HRHB) is dual bearings combination where a hydrodynamic bearing and a rolling bearing with a clearance are assembled coaxially and side by side. The clearance of rolling bearing is a significant parameter for HRHBs. This paper aims to investigate the vibration characteristics of rotor supported by HRHBs to determine the permissible value of clearance of rolling bearing. The maximum dynamic eccentricity ratio is proposed based on the noninterference conditions of rolling bearing and rotor. Then an evaluation method of the maximum dynamic eccentricity ratio is developed. This paper also investigates the effects of the operation parameters such as rotational speed, perturbed force and structure parameters such as bearing span, diameter of rotor, and overhanging length on the maximum dynamic eccentricity ratio. The maximum dynamic eccentricity ratio on the front rolling bearing section is obviously larger than that on the back rolling bearing section. Moreover, the maximum dynamic eccentricity ratio reduces with the increase of the rotational speed and diameter of rotor, but increases with the augmentation of the perturbed force, bearing span, and overhanging length. When the maximum dynamic eccentricity does not go beyond the bound of the radius of the rolling bearing’s clearance circle, the rolling bearing does not interfere with the rotor. The paper provides theoretical basis for design of the minimum value of the rolling bearing’s clearance in HRHBs.

The genetic program of the structural evolution of electric motors with a rolling rotor

The genetic program of functional class of electric motors is first defined and deciphered with a rolling rotor. An element base is defined and genetically possible amount of Class Types are specified. The results of genetic foresight are generalized. Accordance of the real evolution of Types is experimentally confirmed with their genetic program. Directions of further researches are determined.