The Load Acting on Bearings of Rotary Compressor Sliding Vanes

Design Engineering, Volumes 1 and 2 ◽

10.1115/imece2003-41620 ◽

2003 ◽

Author(s):

Yuan Mao Huang ◽

Chien Liang Li

Keyword(s):

Air Pressure ◽

Rotary Compressor ◽

Experimental Setup ◽

Radial Load ◽

Compression Process ◽

Measured Load ◽

Polytropic Process ◽

Study Designs ◽

Further Development ◽

Polytropic Exponent

This study designs extended rods with bearings for vanes and guider slots on covered plates to improve the performance of a sliding vane rotary compressor and determines the load acting on the bearings and vanes. A polytropic process with a polytropic exponent was assumed during the compression process to calculate the air pressure in the vane segments. The air pressure was used with Newton’s law to calculate loads acting on bearings and vanes. A compressor and experimental setup were also built to measure the radial load acting on the bearings. The measured load acting on the bearing was then compared with the calculated results. The exponent constant of 1.05 determined can be used for the further development of the compressor.

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Mechanical Efficiency Optimization of a Sliding Vane Rotary Compressor

Journal of Pressure Vessel Technology ◽

10.1115/1.4000195 ◽

2009 ◽

Vol 131 (6) ◽

Cited By ~ 2

Author(s):

Yuan Mao Huang ◽

San Nan Tsay

Keyword(s):

Genetic Algorithms ◽

Major Axis ◽

Mechanical Efficiency ◽

Rotary Compressor ◽

Friction Forces ◽

Efficiency Optimization ◽

Design Variables ◽

Axis Length ◽

Further Development ◽

Polytropic Exponent

This study presents the mechanical efficiency optimization of a sliding vane rotary compressor by using genetic algorithms. Relevant air properties, volume segments, vane loadings and stresses, friction forces, compression power, and power loss are calculated to determine the mechanical efficiency of a compressor. Design variables include the major axis length and minor axis length of the elliptical stator inner contour, thickness, depth and width of vanes, mechanical efficiency, rotor rotational speed, polytropic exponent, and angular locations of the inlet and outlet ports. The effects of the mutation rate, crossover rate, and population size of the genetic algorithms on these design variables are studied. The vane is thin and the variation effects of vane dimensions on the mechanical efficiency of the compressor are less significant than other design variables. Therefore, the dimensions of vanes can be eliminated as design variables. The mechanical efficiency of the compressor is 0.55. The optimum values of these design variables are recommended for further development of the compressor.

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Measurement of the Air Pressure for a Rotary Vane Compressor

Fluids Engineering ◽

10.1115/imece2003-41351 ◽

2003 ◽

Author(s):

Yuan Mao Huang ◽

Sheng An Yang

Keyword(s):

Frequency Converter ◽

Air Pressure ◽

Cover Plate ◽

Rotary Compressor ◽

Compression Phase ◽

Pressure Transducers ◽

Compressor Rotor ◽

Two Phases ◽

Rotary Vane Compressor ◽

Type Pressure

This study introduces an experimental method that can measure air pressures in the vane segments when a sliding-vane rotary compressor performs suction and compression phases in stable or unstable rotational speeds. When the air pressures of these two phases can be measured, the intake effect of the compressor’s inlet and the seal effect of the vane segments can be evaluated, respectively. Because a frequency converter provides unstable rotational speeds when it controls rotational speeds of a motor with a compressor, an encoder mounted on the output shaft of the motor was applied to record the angular location of the compressor rotor. Two strain gauge type pressure transducers were inserted into the cover plate of the compressor to measure air pressures in the vane segments. Comparing the signals of the encoder with pressure transducers, the air pressures in completions of suction and compression phases could be determined in stable or unstable rotational speeds. The air pressures when the compressor performed suction and compression phases were 99.5 kPa and 153 kPa, respectively, in 1400 rpm. The air pressure when the compressor performed suction phase decreased with the rotational speed faster than 800 rpm. The size or shape of the inlet port of the compressor should be enlarged or modified to provide the suction air pressure without dropping too much. The designed air pressure when the compressor performed compression phase was 244 kPa in 140 rpm, the manufacture precision of the compressor should be increased to decrease leakage.

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Water Jet Applicator for Interface Tissue Removal in Minimally Invasive Hip Refixation: Testing the Principle and Design of Prototype

Journal of Medical Devices ◽

10.1115/1.4043293 ◽

2019 ◽

Vol 13 (2) ◽

Author(s):

Gert Kraaij ◽

Arjo J. Loeve ◽

Jenny Dankelman ◽

Rob G. H. H. Nelissen ◽

Edward R. Valstar

Keyword(s):

Theoretical Analysis ◽

Minimally Invasive ◽

Water Pressure ◽

Minimal Invasive ◽

Outer Diameter ◽

Experimental Setup ◽

Technical Requirements ◽

Tissue Removal ◽

Further Development

Mechanical loosening of implants is in the majority accompanied with a periprosthetic interface membrane, which has to be removed during revision surgery. The same is true if a minimal invasive (percutaneous) refixation of a loose implant is done. We describe the requirements for a waterjet applicator for interface tissue removal for this percutaneous hip refixation technique. The technical requirements were either obtained from a literature review, a theoretical analysis, or by experimental setup. Based on the requirements, a waterjet applicator is designed which is basically a flexible tube (outer diameter 3 mm) with two channels. One channel for the water supply (diameter 0.9 mm) and one for suction to evacuate water and morcellated interface tissue from the periprosthetic cavity. The applicator has a rigid tip (length 6 mm), which directs the water flow to create two waterjets (diameter 0.2 mm), both focused into the suction channel. The functionality of this new applicator is demonstrated by testing a prototype of the applicator tip in an in vitro experimental setup. This testing has shown that the designed applicator for interface tissue removal will eliminate the risk of water pressure buildup; the ejected water was immediately evacuated from the periprosthetic cavity. Blocking of the suction opening was prevented because the jets cut through interface tissue that gets in front of the suction channel. Although further development of the water applicator is necessary, the presented design of the applicator is suitable for interface tissue removal in a minimally invasive hip refixation procedure.

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On the Variation of the Polytropic Exponent in a High Pressure Fan Impeller

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.841.286 ◽

2016 ◽

Vol 841 ◽

pp. 286-291

Author(s):

Andrei Dragomirescu

Keyword(s):

High Pressure ◽

Variable Exponent ◽

Air Flow ◽

Numerical Results ◽

Strong Variation ◽

Polytropic Process ◽

Two Stages ◽

Spiral Casing ◽

Polytropic Exponent

Fan impellers are usually designed considering that the pumped air is incompressible and homogeneous, i.e. its density remains constant. When the incompressibility hypothesis can lead to significant errors, as in the case of high pressure fans, the analysis of the air flow can be made by considering that the air undergoes a polytropic process of constant polytropic exponent. In this paper, the concept of polytropic process of variable exponent depending on impeller radius is introduced, in order to better approximate the phenomena that take place inside blade passages. Numerical results obtained for an impeller of a high pressure fan without spiral casing suggest that the pumped air undergoes two different processes: an expansion in the first part of the impeller and the usual compression in the second part. The two processes are reflected in the strong variation of the polytropic exponent, which shows a vertical asymptote where the change of the process takes place. The results also suggest that high pressure fan impellers could consist of two stages, each stage being designed according to the process that takes place inside it: expansion or compression.

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Research of characteristics of the flow part of an aerothermopressor for gas turbine intercooling air

Proceedings of the Institution of Mechanical Engineers Part A Journal of Power and Energy ◽

10.1177/09576509211057952 ◽

2021 ◽

pp. 095765092110579

Author(s):

Dmytro Konovalov ◽

Mykola Radchenko ◽

Halina Kobalava ◽

Andrii Radchenko ◽

Roman Radchenko ◽

...

Keyword(s):

Gas Turbine ◽

Gas Turbines ◽

Relative Increase ◽

Air Pressure ◽

Pressure Increase ◽

Working Fluid ◽

Compression Process ◽

Two Phase ◽

Pressure Losses ◽

Highly Dispersed

Complex gas turbine schemes with air intercooling are usually used to bring the compression process of working fluid in compressor closer to isothermal one. A promising way to realize it is to use an aerothermopressor. The aerothermopressor is a two-phase jet apparatus, in which the highly dispersed liquid (water) is injected into the superheated gas (air) stream accelerated to the speed closed to the sound speed value (Mach number from 0.8 to 0.9). The air pressure at the aerothermopressor outlet (after diffuser) is higher than at the inlet due to instantaneous evaporation of highly dispersed liquid practically without friction losses in mixing chamber and with an increase in pressure of the mixed homogenous flow. The liquid evaporation is conducted by removing the heat from the air flow. In the course of the experimental research, the operation of the aerothermopressor for gas turbine intercooling air was simulated and its characteristics (hydraulic resistance coefficients, pressure increase, and air temperature) were determined. Within contact cooling of air in the aerothermopressor, the values of the total pressure increase in the aerothermopressor were from 1.02 to 1.04 (2–4%). Thus, the aerothermopressor use to provide contact evaporative cooling of cyclic air between the compressor stages will ensure not only compensation for pressure losses but also provides an increase in total air pressure with simultaneous cooling. Injection of liquid in a larger amount than is necessary for evaporation ensures a decrease in pressure losses in the flow path of the aerothermopressor by 15–20%. When the amount of water flow is more than 10–15%, the pressure loss becomes equal to the loss for the “dry” aerothermopressor, and with a further increase in the amount of injected liquid, they are exceeded. The values of errors in the relative increase of air pressure in the aerothermopressor measurements not exceeded 4%. The results obtained can be used in the practice of designing intercooling systems for gas turbines.

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Ion current studies under various air pressure using a coaxial experimental setup

2017 INSUCON - 13th International Electrical Insulation Conference (INSUCON) ◽

10.23919/insucon.2017.8097169 ◽

2017 ◽

Cited By ~ 2

Author(s):

J. Kortenbrede ◽

A. Cimino ◽

F. Jenau

Keyword(s):

Air Pressure ◽

Ion Current ◽

Experimental Setup

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Storage Power and Efficiency Analysis Based on CFD for Air Compressors Used for Compressed Air Energy Storage

Volume 7: Fluids and Heat Transfer, Parts A, B, C, and D ◽

10.1115/imece2012-88985 ◽

2012 ◽

Cited By ~ 2

Author(s):

Chao Zhang ◽

Terrence W. Simon ◽

Perry Y. Li

Keyword(s):

Heat Transfer ◽

Reynolds Number ◽

Energy Storage ◽

Temperature Rise ◽

Compressed Air ◽

Compressed Air Energy Storage ◽

Compression Process ◽

Aspect Ratios ◽

And Storage ◽

Polytropic Exponent

The compression process in a piston cylinder device in a Compressed Air Energy Storage (CAES) system is studied computationally. Twelve different cases featuring four different compression space length-to-radius aspect ratios and three different Reynolds numbers are studied computationally using the commercial CFD code ANSYS FLUENT. The solutions show that for compression with a constant velocity, the compression can be approximated by a polytropic pressure vs. volume relation. The polytropic exponent, n, characterizes the heat transfer and temperature rise of the air being compressed. For the cases computed, it varies from 1.124 to 1.305 and is found to be more affected by Reynolds number and less by the length-to-radius ratio. Since the efficiency and storage power of the compressor depend on pressure vs. volume trajectory during compression, they are written as functions of the pressure rise ratio and the polytropic exponent, n. The efficiency is high at the beginning of the compression process, and decreases as the compression proceeds. The effect of temperature rise or heat transfer on efficiency and storage power is shown by comparing the efficiency and storage power vs. volume curves having different n values. Smaller temperature rise always results in higher efficiency but lower dimensionless storage power for the same compression pressure ratio. The storage power is used in this study to distinguish the compression process effect (n effect) and the compressor’s size effect on the storage power. The likelihood of flow transitioning into turbulent flow is discussed. A k–ε Reynolds Averaged Navier Stokes (RANS) turbulence model is used to calculate one of the larger Reynolds number cases. The calculated polytropic exponent was only 0.02 different from that of the laminar flow solution. The CFD results show also that during compression, complex vorticity patterns develop, which help mix the cold fluid near the wall with the hot fluid in the inner region, beneficial to achieving a higher efficiency.

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ЧИСЕЛЬНЕ МОДЕЛЮВАННЯ ПРОТОЧНОЇ ЧАСТИНИ МАЛОВИТРАТНОГО АЕРОТЕРМОПРЕСОРА ДЛЯ ПРОМІЖНОГО ОХОЛОДЖЕННЯ ЦИКЛОВОГО ПОВІТРЯ ГАЗОТУРБІННОГО ДВИГУНА

Aerospace technic and technology ◽

10.32620/aktt.2019.4.06 ◽

2019 ◽

pp. 31-38

Author(s):

Дмитро Вікторович Коновалов ◽

Галина Олександрівна Кобалава

Keyword(s):

Gas Turbine ◽

Cfd Simulation ◽

Cooling System ◽

Water Injection ◽

Air Pressure ◽

Injection System ◽

Air Cooling ◽

Compression Process ◽

Evaporation Chamber ◽

Flow Part

A cyclic air intercooling application in the compression process in the compressor has a positive effect on the resource of the gas turbine plant (GTP) and on increasing its capacity without reducing the service life. The most promising method of cooling the cyclic air of the GTP, namely contact cooling by using an aerothermopressor, was analyzed in the paper. This heat exchanger is a two-phase jet apparatus in which, due to the removal of heat from the airflow, the air pressure is increased and its cooling occurs. The main problem in the development of the aerothermopressor is to determine the geometric characteristics of the apparatus flow part and the fluid injection system, which allow its effective application for increasing pressure and fluid spraying fine. An analysis was made of the apparatus models operation by using CFD simulation in the ANSYS Fluent software package to determine the aerothermopressor main characteristics of the cyclic air cooling system of the GTP. The calculation method was determined, the turbulence model was selected, the calculation was carried out taking into account the convergence of the results, and the output data were processed and visualized in the CFD-Post in the form of graphs and fields. Based on this, the aerothermopressor design was developed for a WR-21 gas turbine produced by Rolls Royce. At the first stage of the study, a “dry” aerothermopressor was modeled (without water injection into the evaporation chamber). It was found that the decrease in airflow pressure due to friction losses was about 5%. At the second stage of the study, a simulation of the aerothermopressor with water injection into the flow part (at the inlet to the evaporation chamber) was carried out. As a result of thermogasdynamic compression, the increase in the total air pressure at the outlet of the aerothermopressor was 3.1%, and the temperature of the cooled air was decreased by 280 degrees. To ensure effective air compression in the gas turbine compressor, incomplete evaporation of water in the aerothermopressor was considered. It made it possible to obtain finer water spraying at the diffuser outlet, while the average diameter of the water droplet decreased to 2.5 μm.

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Levitation and Torque Control of PM Synchronous and Induction Type Bearingless Motor

Volume 1B: 16th Biennial Conference on Mechanical Vibration and Noise ◽

10.1115/detc97/vib-4032 ◽

1997 ◽

Author(s):

Yohji Okada ◽

Shigenobu Miyamoto ◽

Satoshi Ueno ◽

Tetsuo Ohishi ◽

C. C. Tan

Keyword(s):

Magnetic Flux ◽

Radial Force ◽

Magnetic Bearing ◽

Torque Control ◽

Experimental Setup ◽

Radial Load ◽

Bearingless Motor ◽

Induction Type ◽

Torque Load ◽

Horizontal Type

Abstract General solution of levitation control applicable to PM synchronous and induction type rotating motor is presented. It is intended for a single rotor to have both functions of magnetic bearing and rotating motor. The rotational control is achieved with the traditional P pole magnetic flux, while the radial force is controlled with either P+2 or P−2 pole magnetic flux in the stator. In the previous work, the proposed general theory of levitated motor is successfully confirmed with no load experiments. In this paper, the load capability of the levitated motor is tested using a horizontal type experimental setup. The stator has 8 concentrated wound electromagnets, each of which is controlled individually by a DSP and power amplifier. The radial load is the gravity of the rotor, while the produced rotating torque is measured with a noncontact variable torque load system. The results obtained are discussed in detail.

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