Wyniki wyszukiwania - BazTech

1

Spindle crash – bearing damages detected by vibration tests

Maier W., Kimmelmann M.

Journal of Machine Engineering

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2017

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Vol. 17, No. 1

46--56

EN

This paper presents experiments regarding the collision of a main spindle with a fixed machine body, i.e. a machine crash. Using experimental tests, it is shown how a machine crash affects the main spindle and its components. After the crash test under laboratory conditions, damages in the form of constrictions and transverse grooves in the bearing rings of the hybrid bearings are detected with roundness tests. Focused on the effects of a crash on high-speed bearings, vibration analyses of the motor spindle are carried out before and after the spindle crash. This paper presents how experimental order tracking analysis and roundness tests can be used to draw conclusions about the spindles’ state, especially about bearing damages caused by the collision.

2

Advancements in centrifugal compressor development for challenging applications

Biba Y., Koch J., Maier W.

Zeszyty Naukowe. Cieplne Maszyny Przepływowe - Turbomachinery / Politechnika Łódzka

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2014

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nr 146

45--46

EN

The lecture provides an overview of challenging compressor applications (in terms of common aerodynamic criteria) focusing on two examples, due to their use of advanced analytical tools and test models. Development of DATUM ICS with Rotating Centrifugal Separator (RCS) technology combined rotary gas-liquid separation and centrifugal compressor flow path. Such a combination represents a new class of turbomachinery and leads to increased system compactness by significantly reducing the size and weight of installed equipment and eliminating large separation vessels often used on traditional compressor trains. An overview is given for the Dresser-Rand RCS development, multiphase mean-line and CFD modeling, and Demo tests, including the latest one at high pressure conditions, more challenging for separation. The test allowed better understanding of the aero- and thermodynamic behavior of the RCS and validated both compression and separation performance at demanding operating conditions. Centrifugal compressors in the refrigeration cycles of LNG production process are characterized by large flow coefficient and high machine Mach number. Therefore both compressed medium and high speed operation directly impact performance. An overview is given on a typical CFD analysis of high-Mach number application stage, along with its test validation on D-R development test rig. Discussion on optimization highlights both the mean-line level of design and analysis, when specialized tools are used for preliminary design, and the CFD level, through parametric studies.

3

TuLiPA - Parsing extensions of TAG with range concatenation grammars

Kallmeyer L., Maier W., Parmentier Y., Dellert J.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2010

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Vol. 58, nr 3

377-391

EN

In this paper we present a parsing framework for extensions of Tree Adjoining Grammar (TAG) called TuLiPA (T¨ubingen Linguistic Parsing Architecture). In particular, besides TAG, the parser can process Tree-Tuple MCTAG with Shared Nodes (TT-MCTAG), a TAGextension which has been proposed to deal with scrambling in free word order languages such as German. The central strategy of the parser is such that the incoming TT-MCTAG (or TAG) is transformed into an equivalent Range Concatenation Grammar (RCG) which, in turn, is then used for parsing. The RCG parser is an incremental Earley-style chart parser. In addition to the syntactic anlysis, TuLiPA computes also an underspecified semantic analysis for grammars that are equipped with semantic representations.

4

Increasing reconfigurability by adaptive module for a lathe

Heisel U., Tonn N., Maier W.

Journal of Machine Engineering

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2008

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Vol. 8, No. 4

5--12

EN

To achieve a higher reconfigurability of machine tools, the Institute for Machine Tools at the University of Stuttgart developed a new spindle module in cooperation with the company INDEX-Werke GmbH & Co. KG (Esslingen, Germany) within the framework of a transfer project (TFB59), supported by the DFG. This spindle module enables the operator to exchange the spindle in clearly less time and hence represents an important device for the reconfigurability of machine tools. This paper describes important steps in the development and design of the new machine module.

5

Linked S2 and S1 design with experimental and CFD verification

Waggott J., Maier W.

Zeszyty Naukowe. Cieplne Maszyny Przepływowe - Turbomachinery / Politechnika Łódzka

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1999

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nr 115

405--412

EN

A precise method of deriving advantageous meridional (S2) flowpath shapes is presented. This design method eliminates radial, or "potential surface" pressure gradients, refines secondary flow, and improves efficiency. The derivation is based on two-dimensional (S1) airfoil or vane shapes and can be applied to most types of turbomachinery. The elimination of radial pressure gradients in high specific speed machines allows the use of airfoils or vanes with less hub to shroud variation. Both CFD calculations and experimental results show that aerodynamic improvements extend far beyond flowpath regions where this design technique is applied.