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Grote, Karl‐Heinrich

doi:10.1007/978-3-662-59711-8_49

Cited by 7 publications

(16 citation statements)

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“…This is confirmed by the fact that quite different diagrams or formulas are found in different data sources. In relevant German textbooks, 1,2,8 one finds the preferred use of diagrams which are almost identical. In contrast, available English textbooks or publications prefer either formulas or data tables.…”

Section: Empirical Relationsmentioning

confidence: 97%

“…For this reason, the empirical relations ku=f(nq) in the form of diagrams, which can be found in many German textbooks, 1,2,8 are used as a reference in the present paper. For readers convenience, these relations are reproduced in Figure 1 for both the Francis and Kaplan turbines.…”

Section: Empirical Relationsmentioning

confidence: 99%

“…This value should be used to limit the application area of Pelton turbines in both the improved and extended Cordier diagrams. In other works, such as Dubbel, 8 the speed number σmax<0.15 is often given. This corresponds to a maximum specific speed nq,max=23.7, which is too high.…”

Section: Cordier Diagram and Extensionmentioning

confidence: 99%

“…7 The application of Cordier diagrams in the field of hydraulic turbines, which is the subject of the present work, can be found, for instance, in various textbooks. 8–11 However, the studies in this regard seem to be generally very limited when compared with those for fans, pumps, and compressors. To fill the gap in this regard, the main objective of the present paper is to discuss, improve, and extend the Cordier diagrams for hydraulic turbines.…”

Section: Introductionmentioning

confidence: 99%

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Improvement and extension of Cordier diagram for hydraulic turbines

Zhang

2022

Proceedings of the Institution of Mechanical Engineers, Part A:

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The Cordier diagram for hydraulic turbines has been accurately improved and extended. The first part of this work completes the Cordier diagram by adding the effect of the number of injector nozzles in Pelton turbines. The Cordier lines (or bands) for Francis and Kaplan turbines have been recalculated based on the use of most available empirical relations without artificial smoothing of the boundaries between the different types of hydraulic turbines. Both turbine type and impeller diameter can be more accurately determined. The part of extending the Cordier diagram is based on the application of design equations for hydraulic turbines and the introduction of the turbine shape factor. This shape factor has a clear physical meaning in contrast to the diameter number in the conventional Cordier diagram. For Pelton turbines, it is representative of the ratio between runner diameter and jet diameter; for Francis and Kaplan turbines, it is representative of the ratio between the height of the wicket gate and the diameter of the impeller. The Cordier diagram for the diameter number can be replaced by the new diagram for the turbine shape factors. Exclusively for Francis turbines, the impeller shape factor also combines the blade profile (angle) at the impeller inlet with design parameters. The method presented in this paper can be well applied to create the extended Cordier diagram for the use of shape factors for pumps and compressors.

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Section: Empirical Relationsmentioning

confidence: 97%

Section: Empirical Relationsmentioning

confidence: 99%

Section: Cordier Diagram and Extensionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Improvement and extension of Cordier diagram for hydraulic turbines

Zhang

2022

Proceedings of the Institution of Mechanical Engineers, Part A:

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“…The vehicle's power is a value that should be available from the data sheet of the vehicle, whereas the contact area between rail and wheel can be calculated. Basis for this is the methodology due to the Hertzian contact area for arbitrarily curved surfaces as it is described in [29]. However, the Hertzian contact area is downsized by a factor of 2/3 to include system-related uncertainties.…”

Section: Traction Power Value (Tpv)mentioning

confidence: 99%

Traffic Load and Its Impact on Track Maintenance

Marschnig¹,

Ehrhart²

2024

Civil Engineering

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Transport volume is often addressed as gross-tonnage when it comes to track degradation, maintenance needs and maintenance costs. Tonnage and thus weight are insufficient to address track loading: The vehicle properties, mainly axle load, unsprung masses and bogie stiffness, as well as train speed have a major impact on track maintenance demand. This chapter gives an overview on vehicle-specific track deterioration models and describes the maintenance needs of different track as well as the influence on track maintenance cost of different vehicles and trains. The approach proposed is both simple enough to be used and sufficiently detailed to address the main technical aspects. The differences of track maintenance necessary for mixed traffic lines, high-speed lines and heavy haul freight lines can be derived from the vehicles used and the existing train speeds. In passenger transport, the difference between push-pull loco hauled trains (with wagons) and multiple units are a major aspect.

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Evolution of the temporal skull openings in land vertebrates: A hypothetical framework on the basis of biomechanics

Werneburg,

Preuschoft

2024

The Anatomical Record

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The complex constructions of land vertebrate skulls have inspired a number of functional analyses. In the present study, we provide a basic view on skull biomechanics and offer a framework for more general observations using advanced modeling approaches in the future. We concentrate our discussion on the cranial openings in the temporal skull region and work out two major, feeding‐related factors that largely influence the shape of the skull. We argue that (1) the place where the most forceful biting is conducted and (2) the handling of resisting food (sideward movements) constitute the formation and shaping of either one or two temporal arcades surrounding these openings. Diversity in temporal skull anatomy among amniotes can be explained by specific modulations of these factors with different amounts of acting forces which inevitably lead to deposition or reduction of bone material. For example, forceful anterior bite favors an infratemporal bar, whereas forceful posterior bite favors formation of an upper temporal arcade. Transverse forces (inertia and resistance of seized objects) as well as neck posture also influence the shaping of the temporal region. Considering their individual skull morphotypes, we finally provide hypotheses on the feeding adaptation in a variety of major tetrapod groups. We did not consider ligaments, internal bone structure, or cranial kinesis in our considerations. Involving those in quantitative tests of our hypotheses, such as finite element system synthesis, will provide a comprehensive picture on cranial mechanics and evolution in the future.

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Allgemeine Tabellen

Cited by 7 publications

References 0 publications

Improvement and extension of Cordier diagram for hydraulic turbines

Improvement and extension of Cordier diagram for hydraulic turbines

Traffic Load and Its Impact on Track Maintenance

Evolution of the temporal skull openings in land vertebrates: A hypothetical framework on the basis of biomechanics

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