scholarly journals New technical solutions for modernization of designs of four-row clonal potato planter

Author(s):  
V.I. Sidorkin ◽  
◽  
M.A. Gaibarya ◽  
N.N. Gapeeva ◽  
◽  
...  

The results of modernization of clonal potato planters are presented to improve the mechanism for adjusting the pitch of planting, which determines the distance between tubers in a row and the density of planting of germinated tubers regardless of the operating conditions of planters and soil-climatic zones of potato cultivation. The design of a variable-speed unit for stepless adjustment of the step and planting density is proposed.

1988 ◽  
Vol 110 (4) ◽  
pp. 472-481 ◽  
Author(s):  
D. C. Sun

A model of the metal V-belt drive (MBD), considering its detailed multiple-band and metal-block structure, and the ratio-change effect during its operation, is constructed and analyzed. A computational scheme is devised that adapts the analysis to the computation of the MBD’s performance for any specified drive-schedule. General performance characteristics of the MBD and an example illustrating its response to a given drive-schedule are presented. The use of the analysis and the computational scheme in the design of the MBD and in finding the optimum operating conditions is discussed.


Author(s):  
K.O. Kobzev ◽  
◽  
S.A. Vyalov ◽  
E.S. Bozhko ◽  
I.A. Zolotuhina ◽  
...  

This article deals with the problem of operating conditions of guide moving crossbars of hydraulic presses. Based on the study of hydraulic press operation processes, the need to develop and implement measures to ensure reliable and trouble-free operation of the press was identified. The conclusion justifies the idea that if these technical solutions are implemented, the service life of hydraulic presses will increase


Machines ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 63 ◽  
Author(s):  
Xavier Escaler ◽  
Toufik Mebarki

A sample of healthy wind turbines from the same wind farm with identical sizes and designs was investigated to determine the average vibrational signatures of the drive train components during normal operation. The units were variable-speed machines with three blades. The rotor was supported by two bearings, and the drive train connected to an intermediate three-stage planetary/helical gearbox. The nominal 2 MW output power was regulated using blade pitch adjustment. Vibrations were measured in exactly the same positions using the same type of sensors over a six-month period covering the entire range of operating conditions. The data set was preliminary validated to remove outliers based on the theoretical power curves. The most relevant frequency peaks in the rotor, gearbox, and generator vibrations were detected and identified based on averaged power spectra. The amplitudes of the peaks induced by a common source of excitation were compared in different measurement positions. A wind speed dependency of broadband vibration amplitudes was also observed. Finally, a fault detection case is presented showing the change of vibration signature induced by a damage in the gearbox.


2019 ◽  
Vol 294 ◽  
pp. 05008
Author(s):  
Dominik Adamski ◽  
Andrzej Białoń ◽  
Zwadka Łukasz

Achieving the interoperability of the European rail system requires many measures to unify technical solutions as well as regulations in each Member State. However, there is a possibility of some incompatibilities between individual subsystems despite generating them in accordance with unified applicable requirements. It is possible that the interoperable rolling stock will not be able to move freely over the interoperable railway line due to some incompatibilities and differences in the versions of the installed firmware in the ERTMS/ETCS system devices. In connection with the above the correct integration of rail vehicles with track-side equipment should be examined by means of tests under operating conditions. The article presents compliance tests of the correct integration of the on-board subsystem with the track-side subsystem which are carried out by the Railway Research Institute.


Author(s):  
M. S. N. Murthy ◽  
Subhash Kumar ◽  
Sheshadri Sreedhara

Abstract A gas turbine engine (GT) is very complex to design and manufacture considering the power density it offers. Development of a GT is also iterative, expensive and involves a long lead time. The components of a GT, viz compressor, combustor and turbine are strongly dependent on each other for the overall performance characteristics of the GT. The range of compressor operation is dependent on the functional and safe limits of surging and choking. The turbine operating speeds are required to be matched with that of compressor for wide range of operating conditions. Due to this constrain, design for optimum possible performance is often sacrificed. Further, once catered for a design point, gas turbines offer low part load efficiencies at conditions away from design point. As a more efficient option, a GT is practically achievable in a split configuration, where the compressor and turbine rotate on different shafts independently. The compressor is driven by a variable speed electric motor. The power developed in the combustor using the compressed air from the compressor and fuel, drives the turbine. The turbine provides mechanical shaft power through a gear box if required. A drive taken from the shaft rotates an electricity generator, which provides power for the compressor’s variable speed electric motor through a power bank. Despite introducing, two additional power conversions compared to a conventional GT, this split configuration named as ‘Part Electric Gas Turbine’, has a potential for new applications and to achieve overall better efficiencies from a GT considering the poor part load characteristics of a conventional GT.


Author(s):  
Nils Trochelmann ◽  
Phillip Bischof Stump ◽  
Frank Thielecke ◽  
Dirk Metzler ◽  
Stefan Bassett

Highly integrated electro-hydraulic power packages with electric motor-driven pumps (EMP) are a key technology for future aircraft with electric distribution systems. State of the art aircraft EMPs are robust but lack efficiency, availability, and have high noise emissions. Variable speed fixed displacement (VSFD-) EMPs, combining a permanent magnet synchronous motor and an internal gear pump, show promising properties regarding noise reduction and energy efficiency. Though, meeting the strict dynamic requirements is tough with this EMP-concept. Speed limitations and inertia impose strong restrictions on the achievable dynamic performance. Moreover, the requirements must be met under a wide range of operating conditions. For a prototype aircraft VSFD-EMP a robust pressure controller design is proposed in this paper. In a first step the operating conditions of the EMP are defined, analyzing environmental conditions and impacts of the interfacing aircraft systems. Nonlinear and linear control design models are developed and validated by measurements at an EMP test rig built for this project. A conventional cascade pressure control concept is selected. This is motivated by the demand for simple, reliable, and proven solutions in aerospace applications. A controller is designed by applying classical loop shaping techniques. Robust stability and performance of the system are investigated through a subsequent μ-analysis. Finally, the controller is tested under nominal and worst case conditions in nonlinear simulations.


2009 ◽  
Vol 10 (2) ◽  
Author(s):  
I Danso ◽  
BN Nuertey ◽  
E Andoh-Mensah ◽  
A Osei-Bonsu ◽  
TEO Asamoah

2021 ◽  
Vol 39 (1A) ◽  
pp. 45-55
Author(s):  
Ahmed H. Al-Hassani ◽  
Alaa R. Al-Badri

The operation and performance of heat-pump systems are affected by indoor and outdoor operating conditions. Power consumption and system efficiency are related to evaporator and condenser working pressures. Intelligent controllers such as a proportional integral (PI) controller improve the performance of variable speed refrigeration systems (VSRs) with electronic expansion valve (EEV). Evaporator and condenser pressures affect the system power consumption and efficiency. In this study, the influence of evaporator and condenser temperatures on the performance of a variable speed refrigeration system with an EEV was experimentally investigated at constant cooling load. The experimental system comprises of a rotary compressor, shell-and-coil condenser, EEV, and shell-and-coil evaporator for one-ton cooling capacity with refrigerant R410. Compressor speed and EEV opening are controlled by a PI controller with two control loops and the refrigerant superheat (DS) is maintained at 7°C. The results show that at constant cooling capacity, the refrigerant flow rate rises with the increase in the compressor speed. The coefficient of performance (COP) is improved with low compressor speed. The System COP is increased by 3.3% with increasing evaporator inlet water temperature for 2°C due to the reduction in the compressor speed and compression ratio. High condenser inlet water temperature promotes the refrigerant subcooling.


Author(s):  
O. V. Kovalenko

Actualuty of the problem. The effective functioning of water-reclamation systems depends to a large extent on the operational reliability and durability of hydraulic structures. The structural elements of hydraulic structures of water management and reclamation complex from the moment of commissioning are subject to aggressive environmental influences. Aggressive factors (hydrostatic water pressure, alternating freezing and thawing, wetting and drying, corrosive action of salts dissolved in water, dynamic action of ice, etc.) constantly affect concrete structures, gradually destroying them. Therefore, the development of measures aimed at ensuring high resistance of structures to the aggressive environmental factors is relevant. Effective operation of structures with long-term aggressive environmental factors is only possible if they are protected (reinforced) with effective insulating, anticorrosive, high-strength, wear-resistant and cavitation-resistant composite materials. Specific characteristics of polymer and polymer-cement composite materials (high strength, corrosion resistance, frost resistance, adhesion to different coatings) enable to create effective technologies for restoring the functional capacity of hydraulic structures and increasing their stability. The need of reinforcing concrete structures of hydraulic facilities by combining or partially replacing them with modern composite materials and structures made of polymers and polymer cement is determined in view of increasing coolness, reliability and durability of the structures. These materials should be standardized at the stage of design, construction, repair and reconstruction of structures that will ensure their operational reliability and durability in aggressive environment. The development and implementation of technical solutions increasing the operational reliability and durability of hydraulic facilities for water-reclamation purposes while reducing their material and metal intensity are ones of the main areas of scientific research in the field of construction, repair and reconstruction of water-reclamation systems. Achieving high technical and economic performance of hydraulic facilities, taking into account the significant effect of aggressive environmental factors on them is possible using a scientifically sound combination of concrete and reinforced concrete structures with polymer and polymer cement composite materials. The highest level of reliability will be ensured by the structures providing the protection against damage, corrosion and filtration using the latest high performance composite materials. Optimization of technical solutions to increase the operational reliability and durability of hydraulic facilities is only possible provided that modern composite materials properties are comprehensively studied, their compliance with the requirements of water and reclamation construction, taking into account extreme operating conditions, is determined and new efficient technologies for future performance of the facilities are created. Along with expanding the use of polyme and polymer-cement composite materials, finding new varieties of polymer additives and obtaining reliable data on the durability of these materials in different operating conditions will be extended. Results. The Institute of Water Problems and Land Reclamation of NAAS has developed the main technological areas of polymer and polymer-cement composite materials application for increasing the operational reliability of hydraulic structures of water management and reclamation complex: polymeric film screens and geomembranes for increasing the anti-filtration properties; polymer and bitumen-polymer sealants for the arrangement and restoration of deformation joints; polymer and polymer-cement mixtures for structural repairs, restoration of bearing capacity, waterproofing protection, protection against filtration, accidental damage, corrosion, cavitation and actuation of hydraulic structures; concrete polymers, polymer concrete and polymer cement with high physical and mechanical properties for construction, repair and reconstruction of hydraulic structures.


2021 ◽  
Vol 2094 (4) ◽  
pp. 042082
Author(s):  
M S Rublev ◽  
M S Sitnikov ◽  
A A Goriunov ◽  
A V Filimonov ◽  
A A Shakirov

Abstract The use of mathematical modelling at the early stages of product design makes it possible to substantiate fundamental technical solutions, taking into account all possible (large number) requirements for the product by consumers and operation. At this (early) stage, it is important to use well-tested and convenient tools for designers to create virtual stands and digital twins (DC), confirming compliance, as well as forming the structure of systems and products as a whole. The article discusses a comprehensive methodology for the process of constructing a numerical model of a locomotive for analysing dynamics under various operating conditions. It is based on the top-level structural model (LBM), which is presented in the form of a block diagram and is used at all stages of product design. The required detailing of such a model depends on the actual tasks. The detailed models of the systems that have been developed within the framework of the work are presented.


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