scholarly journals Water as a Refrigerant in Centrifugal Compressor Cooling Systems for Industrial Applications

2019 ◽  
Author(s):  
Florian Hanslik ◽  
Juergen Suess
Keyword(s):  
Centrifugal Compressor ◽  
Industrial Applications ◽  
Cooling Systems

Development and Industrial Application of the “All-Over-Controlled Vortex Distribution Method” for Designing Radial and Mixed Flow Impellers

1992 ◽  
Author(s):  
S. J. Wang ◽  
M. J. Yuan ◽  
G. Xi ◽  
S. X. Liu ◽  
D. T. Qi ◽  
...  
Keyword(s):  
Flow Field ◽  
Centrifugal Compressor ◽  
Inverse Method ◽  
Three Dimensional ◽  
Industrial Applications ◽  
Mixed Flow ◽  
Distribution Method ◽  
Stream Surface ◽  
Surface Theory ◽  
Performance Curves

Sixteen years ago an inverse method of designing radial, mixed flow impellers was proposed by the first author of this paper, which was based on a quasi-three-dimensional stream surface theory. The contradictions between the full controlling of the flow field in the whole impeller and the designed bables’ smooth machinability can be perfectly resolved with the above method (So it is called “all-over-controlled vortex distribution method”). This paper presents the developments and industrial applications of the above method in the last decade. Two single centrifugal compressor model stages with the 3-D impellers designed by this method are studied in detail, and several performance curves of the multistage centrifugal compressors designed by this method are also presented.

Condensation Induced Shock in Thermal/Fluid Systems

2012 ◽  
Author(s):  
Amir Jokar ◽  
Erik W. Christiansen
Keyword(s):  
Shock Waves ◽  
Phase Change ◽  
Air Conditioning ◽  
Industrial Applications ◽  
Governing Equations ◽  
Cooling Systems ◽  
Heating And Cooling ◽  
Fluid Systems ◽  
Air Conditioning Systems ◽  
Effective Life

Phase-change through condensation and evaporation processes takes place in many daily-use heating and cooling systems. However, if these processes experience uncontrolled pressure and temperature conditions, shock waves may be generated. Depending on the strength and conditions of the generated waves, they can decrease the effective life of equipment or even cause devastating destruction. Cavitation and water hammer phenomena are examples of flow issues that are well understood and reported in thermal/fluid systems, although not many studies have been published in open literature on condensation-induced shock (CIS) with the applications in refrigeration and air conditioning systems. This study reviews the limited literature on this topic, analyze the complex CIS phenomenon, derives and solves the governing equations, presents the results of typical conditions that may happen in different residential and industrial applications, and provides ways to avoid devastating incidents that may occur as a result of this phenomena.

Experimental Investigation of the Diffuser Vane Clearance Effect in a Centrifugal Compressor Stage With Adjustable Diffuser Geometry: Part II—Detailed Flow Analysis

2014 ◽  
Vol 137 (3) ◽  
Author(s):  
Stefan Ubben ◽  
Reinhard Niehuis
Keyword(s):  
Centrifugal Compressor ◽  
Pressure Ratio ◽  
Flow Analysis ◽  
Industrial Applications ◽  
Experimental Investigations ◽  
Stall Margin ◽  
Diffuser Flow ◽  
Radial Gap ◽  
The Impact ◽  
Vane Angle

Adjustable diffuser vanes offer an attractive design option for centrifugal compressors applied in industrial applications. However, the knowledge about the impact on compressor performance of a diffuser vane clearance between vane and diffuser wall is still not satisfying. This two-part paper summarizes results of experimental investigations performed with an industrial-like centrifugal compressor. Particular attention was directed toward the influence of the diffuser clearance on the operating behavior of the entire stage, the pressure recovery in the diffuser, and on the diffuser flow by a systematic variation of the parameters diffuser clearance height, diffuser vane angle, radial gap between impeller exit and diffuser inlet, and rotor speed. In Part I it was shown that an one-sided diffuser clearance is able to contribute to an increase in flow range, stall margin, pressure ratio, and efficiency. In order to reveal the relevant flow phenomena, in Part II the results of detailed measurements of the pressure distribution at diffuser exit and particle image velocimetry (PIV) measurements inside the diffuser channel performed at three clearance configurations and three diffuser angles at a fixed radial gap are discussed. It was found that, for defined diffuser configurations, the clearance flow amplifies the diffuser throat vortex capable to reduce the loading of the highly loaded vane pressure side and to support a more homogenous diffuser flow. It turned out that the co-action of the geometry parameter diffuser vane angle and diffuser clearance height is of particular importance. The experimental results are published as an open computational fluid dynamics (CFD) testcase “Radiver 2.”

Experimental Investigation of the Diffuser Vane Clearance Effect in a Centrifugal Compressor Stage With Adjustable Diffuser Geometry—Part I: Compressor Performance Analysis

2014 ◽  
Vol 137 (3) ◽  
Author(s):  
Stefan Ubben ◽  
Reinhard Niehuis
Keyword(s):  
Centrifugal Compressor ◽  
Negative Impact ◽  
Pressure Ratio ◽  
Industrial Applications ◽  
Experimental Investigations ◽  
Flow Measurements ◽  
Flow Phenomena ◽  
Compressor Performance ◽  
Compressor Map ◽  
The Impact

Adjustable diffuser vanes offer an attractive design option for centrifugal compressors applied in industrial applications. However, the knowledge about the impact on compressor performance of a diffuser vane clearance between vane and diffuser wall is still not satisfying. This two-part paper summarizes results of experimental investigations performed with an industrial-like centrifugal compressor. Particular attention was directed toward the influence of the diffuser clearance on the operating behavior of the entire stage, the pressure recovery in the diffuser, and on the diffuser flow by a systematic variation of the parameters diffuser clearance height, diffuser vane angle, radial gap between impeller exit and diffuser inlet, and rotor speed. Compressor map measurements provide a summary of the operating behavior related to diffuser geometry and impeller speed, whereas detailed flow measurements with temperature and pressure probes allow a breakdown of the losses between impeller and diffuser and contribute to a better understanding of relevant flow phenomena. The results presented in Part I show that an one-sided diffuser clearance does not necessarily has a negative impact on the operation and loss behavior of the centrifugal compressor, but instead may contribute to an increased pressure ratio and improved efficiency as long as the diffuser passage is broad enough with respect to the clearance height. The flow phenomena responsible for this detected performance behavior are exposed in Part II, where the results of detailed measurements with pressure probes at diffuser exit and particle image velocimetry (PIV) measurements conducted inside the diffuser channel are discussed. The experimental results are published as an open computational fluid dynamics (CFD) testcase “Radiver 2.”

Porous Alumina-Zirconia Prepared by Foam Technique for Applications as Cooling Systems of Artificial Satellites

2008 ◽  
Vol 591-593 ◽  
pp. 865-869
Author(s):  
Ana Coh O. Hirschmann ◽  
Maria do Carmo de Andrade Nono ◽  
R.R. Riehl ◽  
Cosme Roberto Moreira Silva
Keyword(s):  
Porous Alumina ◽  
Mercury Porosimetry ◽  
Heat Pipes ◽  
Porous Ceramics ◽  
Industrial Applications ◽  
Artificial Satellites ◽  
High Porosity ◽  
Cooling Systems ◽  
Uniform Microstructure ◽  
New Applications

The interest in porous ceramics has increased concurrently with new processes and new applications. This material has been used in several industrial applications such as filters, catalysis and sensors. The objective of the present investigation was to produce porous alumina with 3 % mol yttria stabilized zirconia in tetragonal crystalline structure (Y-TZP). This material will be used in cooling systems of satellites, due to its mechanical properties and chemical inertia. To obtain the porous ceramics was used the direct foaming technique, which is a method based on the preparation of a stable foam slurry and a slurry of alumina and zirconia that are later mixed and blended for incorporation of air in the mixture. The sintered ceramics was characterized by scanning electronic microscopy, mercury porosimetry and permeability measurements. The porous Al2O3–ZrO2 ceramics obtained showed high porosity and uniform microstructure with 20–100 ,m open pores. The results from these alumina zirconia composites showed a potential to apply in heat pipes.

Experimental Investigation of the Diffuser Vane Clearance Effect in a Centrifugal Compressor Stage With Adjustable Diffuser Geometry: Part I — Compressor Performance Analysis

2014 ◽  
Author(s):  
Stefan Ubben ◽  
Reinhard Niehuis
Keyword(s):  
Centrifugal Compressor ◽  
High Efficiency ◽  
Negative Impact ◽  
Pressure Ratio ◽  
Industrial Applications ◽  
Flow Measurements ◽  
Flow Phenomena ◽  
Compressor Performance ◽  
Compressor Map ◽  
The Impact

The combination of variable speed control and adjustable diffuser vanes offers an attractive design option for centrifugal compressors applied in industrial applications where a wide operating range at high efficiency level and a favorable surge line is required. However, the knowledge about the impact on compressor performance of a diffuser vane clearance between vane and diffuser wall which is mandatory since the diffuser geometry adjustment has to take place during operation, is still not satisfying. This two-part paper summarizes results of investigations performed at the Institute of Jet Propulsion and Turbomachinery at RWTH Aachen with an industrial-like centrifugal compressor, featuring a design pressure ratio of 4 and a design speed of 35200 rpm. Particular attention was directed to the influence of the diffuser clearance on the operating behavior of the entire stage, the pressure recovery in the diffuser and on the diffuser flow by a systematic variation of the parameters diffuser clearance height, diffuser vane angle, radial gap between impeller exit and diffuser inlet, and rotor speed. Compressor map measurements provide a summary of the operating behavior related to diffuser geometry and impeller speed, whereas detailed flow measurements with temperature and pressure probes allow a breakdown of the losses between impeller and diffuser and contribute to a better understanding of relevant flow phenomena. The results presented in Part I show that an one-sided diffuser clearance does not necessarily has a negative impact on the operation and loss behavior of the centrifugal compressor, but instead may contribute to an increased pressure ratio and improved efficiency. The flow phenomena responsible for this detected performance behavior are exposed in Part II [28], where the results of detailed measurements with pressure probes at diffuser exit and Particle Image Velocimetry (PIV) measurements conducted inside the diffuser channel, revealing the complex and unsteady flow leaving the impeller and passing the diffuser channel, are discussed. The experimental results are published as an open CFD testcase “Radiver 2” [26], extending the experimental data base of the testcase “Radiver” published in 2003 by Ziegler [31].

Flow-Driven Design Optimization of Centrifugal Compressor Volutes for Turbochargers

2019 ◽  
Author(s):  
Andrea Tanganelli ◽  
Giulia Andreini ◽  
Matteo Rossini ◽  
Francesco Balduzzi ◽  
Alessandro Bianchini ◽  
...  
Keyword(s):  
Design Optimization ◽  
Cross Section ◽  
Entropy Generation ◽  
Centrifugal Compressor ◽  
Industrial Applications ◽  
Operating Conditions ◽  
Generation Rate ◽  
Entropy Generation Rate ◽  
Mass Flow Rates ◽  
The Cross

Abstract The design of the volute (in terms of area distribution and shape of the cross section) has a relevant impact on the efficiency and the operating range of a centrifugal compressor. This latter aspect is even more relevant in turbochargers, where the compressor has to cover a functioning range much wider than that of industrial applications. In addition, beyond conventional aerodynamic requirements, the design of the cross section shape is driven often in these applications also by space constraints imposed by the vehicle layout, leading to a variety of volute layouts. In a previous study, some of the authors highlighted the prospects of using the entropy generation rate to evaluate the losses within a volute, since this parameter allows an exact localization of irreversibilities. Starting from these results, the present study shows the suitability of this parameter as an indicator for the fine design optimization of the volute shape. A methodology is presented, which, based on the CFD computed contours of both the entropy generation rate and the total pressure, is able to drive the fine optimization of the volute cross-section at different azimuthal positions in order to maximize its efficiency. Multiple volute shapes are analysed in the paper and the effect of the operating conditions is accounted for by investigating different mass flow rates. The proposed approach indeed lead to a maximization of the volute efficiency with only a few trials and it could indeed provide room for future automatized fine optimization strategies.

High Hub/Tip Ratio Centrifugal Compressors

2009 ◽  
Author(s):  
C. Rodgers ◽  
D. Brown
Keyword(s):  
Centrifugal Compressor ◽  
Gas Turbines ◽  
Rapid Development ◽  
Design Feature ◽  
Industrial Applications ◽  
Design Parameters ◽  
Centrifugal Compressors ◽  
Ww Ii ◽  
Turbomachinery Design ◽  
Compressor Technology

During WW II the impetus of higher speed higher altitude aircraft necessitated the rapid development of advanced supercharged and turbocharged piston engines, much of the centrifugal compressor technology from which was transferred to early gas turbines. Post WW II gas turbine development was predominantly focused upon the perfection of the multistage axial compressors, with the recognition that in certain applications the combined axial–cum–centrifugal compressor (AxC) could provide a more compact engine installation. Gas Turbines with AxC compressors now fulfill a significant sector of the aviation propulsion market, plus also some industrial applications. Individual research and development of both axial and centrifugal compressors types continues to higher plateaus of performance, and is the context of extensive publications, yet in difference a scarcity of written technology prevails for the AxC compressor. This conspicuous limited exposure of AxC compressor technology fostered the motivation for this treatise, the intent being to record whatever meager AxC information at large exists, plus highlighting turbomachinery design parameters which can assist in AxC continued performance perfection. Specifically a characteristic design feature of AxC examined is the influence of large impeller hub to tip diameter ratios Є.

The Application of Ultra-Thin Sectioning Techniques to Non-Biological Samples

1968 ◽  
Vol 26 ◽  
pp. 332-333
Author(s):  
C. F. Oster
Keyword(s):  
Biological Sciences ◽  
Epoxy Resin ◽  
Cross Sections ◽  
Biological Samples ◽  
Industrial Applications ◽  
Photographic Film ◽  
Silver Particles ◽  
Thin Sectioning ◽  
Embedding Medium

Although ultra-thin sectioning techniques are widely used in the biological sciences, their applications are somewhat less popular but very useful in industrial applications. This presentation will review several specific applications where ultra-thin sectioning techniques have proven invaluable.The preparation of samples for sectioning usually involves embedding in an epoxy resin. Araldite 6005 Resin and Hardener are mixed so that the hardness of the embedding medium matches that of the sample to reduce any distortion of the sample during the sectioning process. No dehydration series are needed to prepare our usual samples for embedding, but some types require hardening and staining steps. The embedded samples are sectioned with either a prototype of a Porter-Blum Microtome or an LKB Ultrotome III. Both instruments are equipped with diamond knives.In the study of photographic film, the distribution of the developed silver particles through the layer is important to the image tone and/or scattering power. Also, the morphology of the developed silver is an important factor, and cross sections will show this structure.

The mensuration of interfaces

1992 ◽  
Vol 50 (1) ◽  
pp. 216-217
Author(s):  
W.M. Stobbs
Keyword(s):  
Electron Microscopy ◽  
50Th Anniversary ◽  
Numerical Data ◽  
Industrial Applications ◽  
Dynamical Theory ◽  
Large Strains ◽  
Reasonable Approach ◽  
Lattice Resolution ◽  
Analogue To Digital ◽  
The Way

I do not have access to the abstracts of the first meeting of EMSA but at this, the 50th Anniversary meeting of the Electron Microscopy Society of America, I have an excuse to consider the historical origins of the approaches we take to the use of electron microscopy for the characterisation of materials. I have myself been actively involved in the use of TEM for the characterisation of heterogeneities for little more than half of that period. My own view is that it was between the 3rd International Meeting at London, and the 1956 Stockholm meeting, the first of the European series , that the foundations of the approaches we now take to the characterisation of a material using the TEM were laid down. (This was 10 years before I took dynamical theory to be etched in stone.) It was at the 1956 meeting that Menter showed lattice resolution images of sodium faujasite and Hirsch, Home and Whelan showed images of dislocations in the XlVth session on “metallography and other industrial applications”. I have always incidentally been delighted by the way the latter authors misinterpreted astonishingly clear thickness fringes in a beaten (”) foil of Al as being contrast due to “large strains”, an error which they corrected with admirable rapidity as the theory developed. At the London meeting the research described covered a broad range of approaches, including many that are only now being rediscovered as worth further effort: however such is the power of “the image” to persuade that the above two papers set trends which influence, perhaps too strongly, the approaches we take now. Menter was clear that the way the planes in his image tended to be curved was associated with the imaging conditions rather than with lattice strains, and yet it now seems to be common practice to assume that the dots in an “atomic resolution image” can faithfully represent the variations in atomic spacing at a localised defect. Even when the more reasonable approach is taken of matching the image details with a computed simulation for an assumed model, the non-uniqueness of the interpreted fit seems to be rather rarely appreciated. Hirsch et al., on the other hand, made a point of using their images to get numerical data on characteristics of the specimen they examined, such as its dislocation density, which would not be expected to be influenced by uncertainties in the contrast. Nonetheless the trends were set with microscope manufacturers producing higher and higher resolution microscopes, while the blind faith of the users in the image produced as being a near directly interpretable representation of reality seems to have increased rather than been generally questioned. But if we want to test structural models we need numbers and it is the analogue to digital conversion of the information in the image which is required.

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