scholarly journals Prospects of Using Hydrodynamic Cavitation for Enhancement of Efficiency of Fluid Working Medium Preparation Technologies

2018 ◽  
Vol 62 (4) ◽  
pp. 269-276 ◽  
Author(s):  
Anatolii Fesenko ◽  
Fatyma Yevsiukova ◽  
Yevheniia Basova ◽  
Maryna Ivanova ◽  
Vitalii Ivanov
Keyword(s):  
Estimation Procedure ◽  
Hydrodynamic Cavitation ◽  
Working Fluid ◽  
Optimization Of Parameters ◽  
Energy Parameters ◽  
Working Medium ◽  
Medium Preparation

In this article a hardware estimation procedure and optimization of parameters of working fluid cavitation processing are proposed. Here the basic aspects of preparation efficiency and using of water-fuel emulsion are reviewed. An example of estimation of energy parameters of hydrodynamic activator operation in obtaining water-fuel emulsion is supplied.

scholarly journals Thermodynamic Analysis of Irreversible Desiccant Systems

Entropy ◽  
2018 ◽  
Vol 20 (8) ◽  
pp. 595 ◽  
Author(s):  
Niccolò Giannetti ◽  
Seiichi Yamaguchi ◽  
Andrea Rocchetti ◽  
Kiyoshi Saito
Keyword(s):  
Control Volume ◽  
Ideal Gas ◽  
Maximum Efficiency ◽  
Working Fluid ◽  
Specific System ◽  
Equilibrium Relationship ◽  
Working Medium ◽  
Vapour Mixture ◽  
Energy Balances ◽  
Relationship Of

A new general thermodynamic mapping of desiccant systems’ performance is conducted to estimate the potentiality and determine the proper application field of the technology. This targets certain room conditions and given outdoor temperature and humidity prior to the selection of the specific desiccant material and technical details of the system configuration. This allows the choice of the operative state of the system to be independent from the limitations of the specific design and working fluid. An expression of the entropy balance suitable for describing the operability of a desiccant system at steady state is obtained by applying a control volume approach, defining sensible and latent effectiveness parameters, and assuming ideal gas behaviour of the air-vapour mixture. This formulation, together with mass and energy balances, is used to conduct a general screening of the system performance. The theoretical advantage and limitation of desiccant dehumidification air conditioning, maximum efficiency for given conditions constraints, least irreversible configuration for a given operative target, and characteristics of the system for a target efficiency can be obtained from this thermodynamic mapping. Once the thermo-physical properties and the thermodynamic equilibrium relationship of the liquid desiccant mixture or solid coating material are known, this method can be applied to a specific technical case to select the most appropriate working medium and guide the specific system design to achieve the target performance.

scholarly journals Engineered Lateral Roughness Element Implementation and Working Fluid Alteration to Intensify Hydrodynamic Cavitating Flows on a Chip for Energy Harvesting

Micromachines ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 49 ◽  
Author(s):  
Moein Talebian Gevari ◽  
Ali Hosseinpour Shafaghi ◽  
Luis Guillermo Villanueva ◽  
Morteza Ghorbani ◽  
Ali Koşar
Keyword(s):  
Energy Harvesting ◽  
Microfluidic Devices ◽  
Surface Cleaning ◽  
Hydrodynamic Cavitation ◽  
Working Fluid ◽  
Wall Roughness ◽  
Cavitating Flows ◽  
Roughness Elements ◽  
Fluid Alteration ◽  
On Chip

Hydrodynamic cavitation is considered an effective tool to be used in different applications, such as surface cleaning, ones in the food industry, energy harvesting, water treatment, biomedical applications, and heat transfer enhancement. Thus, both characterization and intensification of cavitation phenomenon are of great importance. This study involves design and optimization of cavitation on chip devices by utilizing wall roughness elements and working fluid alteration. Seven different microfluidic devices were fabricated and tested. In order to harvest more energy from cavitating flows, different roughness elements were used to decrease the inlet pressure (input to the system), at which cavitation inception occurs. The implemented wall roughness elements were engineered structures in the shape of equilateral triangles embedded in the design of the microfluidic devices. The cavitation phenomena were also studied using ethanol as the working fluid, so that the fluid behavior differences in the tested cavitation on chip devices were explained and compared. The employment of the wall roughness elements was an effective approach to optimize the performances of the devices. The experimental results exhibited entirely different flow patterns for ethanol compared to water, which suggests the dominant effect of the surface tension on hydrodynamic cavitation in microfluidic channels.

Stainless Steels as Erosion Resistant Materials for Hydraulic Machines

2017 ◽  
Vol 750 ◽  
pp. 75-79
Author(s):  
Brandusa Ghiban ◽  
Carmen Anca Safta ◽  
Vlad Motoiu
Keyword(s):  
Steam Turbine ◽  
Geothermal Energy ◽  
Electric Energy ◽  
Heat Energy ◽  
Hydrodynamic Cavitation ◽  
Metallic Surface ◽  
Working Fluid ◽  
Corrosion Mechanism ◽  
Hydraulic Machines ◽  
Abrasive Erosion

The corrosion phenomena lead to serious modifications in the structure of metallic materials from which are manufactured the important active components of hydraulic machines. There are two important types of corrosion: cavitation and silt erosion (abrasive erosion), that are specific to machines which are producing energy [1, 2, 3]. As a corrosion mechanism, in hydrodynamic cavitation [4, 5], when cavitation bubbles implode on the solid surface of hydraulic machine component, the local pressure developed is high and can exceed the fatigue strength, yield point or compression strength of the material. Cavitation phenomenon can be produced in different ways. Four types of cavitation are described in the literature, looking for the method of producing, [6]: hydrodynamic cavitation, particle cavitation, acoustic cavitation, and optic cavitation. Abrasive erosion is the gradual degradation of a structure under the action of solid particles suspended in the working fluid. Impact and sliding erosion are the main categories of abrasive erosion approached in the literature by considering the mechanisms of which the abrasive particles act on the metallic surface, [2]. In the last decades the abrasive erosion phenomenon became a serious problem for the efficient operation of power plants, for instance in hydropower plants [7, 8]. Geothermal energy is the heat energy of the earth given by capturing the springs of heat water. In Romania the geothermal energy is used only for heating because the water has a low temperature and cannot be used to produce electric energy, only heat energy. So, although Romania is the third highest potential geothermal in Europe, practically electric energy from geothermal resource has a low thermal potential, [9]. A steam turbine is working at high rotational speed, high temperatures and using the working fluid which could be steam or wet steam. The working fluid is composed of corrosive chemicals with an aggressive pH. For this reason the common problems of the geothermal steam turbine failures are given by fractures of the blades (rotor blades or stator blades).

scholarly journals Combined Cycles for Pipeline Compressor Drives Using Heat

1979 ◽  
Author(s):  
W. F. Malewski ◽  
G. M. Holldorff
Keyword(s):  
Gas Turbines ◽  
Waste Heat ◽  
Working Fluid ◽  
Exhaust Gas ◽  
Working Fluids ◽  
Ambient Temperatures ◽  
Working Medium ◽  
Medium Range ◽  
Combined Cycles ◽  
Optimum Working

Combined cycles for pipeline-booster stations using waste heat from gas turbines exhaust can improve the overall efficiency of such stations remarkably. Several working fluids are suitable. Due to existing criteria for selecting a working medium under mentioned conditions, water, ammonia, propane and butane can be considered as practical working fluids. The investigations have shown that: (a) ammonia is advantageous at low exhaust gas and ambient temperatures, (b) water is most effective at high exhaust gas and ambient temperatures, and (c), additionally, hydrocarbons are suitable in a medium range for exhaust gas and condensing temperatures. Not only thermodynamic but also operational features have to be considered. There is not one optimum working fluid but a best one suitable according to the prevailing site conditions.

The Comparison and Parameters Optimization for the Mixed Intermediate Fluid of Intermediate Fluid Vaporizer

2019 ◽  
Author(s):  
Yan Yan ◽  
Yuxing Li ◽  
Shuo Wang
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Performance ◽  
Parameters Optimization ◽  
Working Fluid ◽  
Transfer Model ◽  
Transfer Performance ◽  
Safe Operation ◽  
Exchange Area ◽  
Working Medium ◽  
Different Types

Abstract In this paper, an establishment of heat transfer model is performed to study the effects of different types of mixed intermediate fluid on the vaporizer performance. It is found that compared with pure propane, mixed ethane-propane working fluid can bring about a reduction of 10% ∼ 25% for the heat exchange area of intermediate fluid vaporizer IFV. In addition, using mixed butane-propane working medium could stabilize the saturated pressure of intermediate fluid at a relatively low level of 0.2 MPa, while the saturated pressure of pure propane ranges from 0.33 MPa to 0.65 MPa. Thereby, the former one is more reliable than the latter one in an aspect of safe operation. Moreover, after an investigation and selection, the results show that the saturated pressure of intermediate fluid varying from 0.3 MPa to 0.6 MPa and the amount of LNG overloaded over than 130% is beneficial for the improvement of comprehensive heat transfer performance of IFV.

scholarly journals Visualization research on the influence of an ultrasonic degassing system on the operation of a hydraulic gear pump

2018 ◽  
Vol 211 ◽  
pp. 03005 ◽  
Author(s):  
Piotr Antoniak ◽  
Jarosław Stryczek ◽  
Michał Banaś ◽  
Oleksandr Lyhovskyi ◽  
Ihor Gryshko ◽  
...  
Keyword(s):  
High Speed ◽  
Theoretical Description ◽  
Working Fluid ◽  
Operating Parameters ◽  
Gear Pump ◽  
Hydraulic Systems ◽  
Chemical Methods ◽  
Physical Methods ◽  
Working Medium ◽  
Gear Pumps

Gear pumps make a group of the most popular hydraulic energy generators. Research and development works concerning those units have been going on for decades, and thanks to them gear pumps feature very good operating parameters. However, even well-designed gear pumps will not work properly if the physical properties of the working fluid are incorrect. One of such properties is compressibility of the fluid, which largely depends on the amount of gas dissolved in the medium. For this reason, the aim is to reduce the amount of gas dissolved in the working medium. It can be done using both chemical and physical methods. Because chemical methods can affect the chemical composition of the working fluid, it is the physical methods that are usually used in hydraulic systems. This paper presents preliminary visualization research into the influence of an ultrasonic degassing system on the operation of a hydraulic gear pump. Apart from that, operation of such a system and its theoretical impact on the work of the gear pump is discussed Experimental study, using a high-speed camera, was carried out in order to verify the theoretical description.

scholarly journals Combined system of energy generation from biomass and solar energy

2018 ◽  
Vol 49 ◽  
pp. 00132
Author(s):  
Renata Włodarczyk ◽  
Robert Zarzycki ◽  
Zbigniew Bis
Keyword(s):  
Renewable Energy ◽  
Solar Energy ◽  
Intelligent System ◽  
Renewable Energy Sources ◽  
Public Utility ◽  
Working Fluid ◽  
Combined System ◽  
Working Medium ◽  
Additional Equipment ◽  
Automation And Control

The study discussed the design and principle of operation of an intelligent system that uses renewable energy sources (RES) in the form of biomass and solar energy. The aim of the system is to supply heat to public utility buildings in Częstochowa, Poland. The system of renewable energy conversion includes boilers fuelled by biomass in the form of pellets and evacuated tube solar collectors. An additional equipment for the system is buffer tanks, computer-aided monitoring of operating parameters of the system and calorimeters with the system of automation and control of the system operation. The study discusses possible problems with the use of solar installations and processes of degradation of metal components, glass tubes and working medium. The basic criteria that have to be met by the working fluid in the system, parameters that have to be periodically controlled during the use of solar installations and mixtures of fluids available in the renewable energy market were presented.

Failure Analysis of a Low-Temperature Energy Conversion System Using Organic Rankine Cycles

2013 ◽  
Vol 864-867 ◽  
pp. 2127-2131
Author(s):  
Li Li Wei ◽  
Yu Feng Zhang ◽  
Yong Chao Mu
Keyword(s):  
Energy Conversion ◽  
Rankine Cycle ◽  
Working Fluid ◽  
Practical Reasons ◽  
Medium Temperature ◽  
Water Steam ◽  
Design And Optimization ◽  
Working Medium ◽  
Conversion Unit ◽  
Organic Fluids

It is widely believed that Rankine cycle power plant using organic fluids as the working medium has advantages over conventional Rankine cycle with water steam as the working medium in low-to-medium temperature heat conversion. It is also testified in the market. However, besides the integration of the cycle and the characteristic of the working fluid, the design and debugging of the energy conversion unit are also important part in acquiring good performance. In this research some phenomenon of failure is investigated. Accordingly, the theoretical and practical reasons and solutions are obtained. It provides good guideline on the design and optimization of the energy conversion unit.

Analysis on the Selection of Working Fluid in the Small Diameter Gravity Heat Pipe - Based on a New Passive Technology

2013 ◽  
Vol 368-370 ◽  
pp. 661-665 ◽  
Author(s):  
Jian Liang Ju ◽  
Zhi Gang Zhang ◽  
Wei Zhang
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Small Diameter ◽  
Working Fluid ◽  
Working Pressure ◽  
Working Temperature ◽  
Working Medium ◽  
Heat Transfer Limit ◽  
Thermal Physical Properties ◽  
Selection Of

This paper discusses the suitable working fluid applying in small diameter (millimeter scale) gravity heat pipe theoretically. The working temperature, characteristics of material, heat transfer limit and thermal physical properties of working medium of the heat pipe were studied. It is concluded that each aspect capability of heat transfer of R717 is excellent, but its working pressure is a bit high; the synthesized capability of R134a is relatively ideal and can be chosen as the working medium.

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