Numerical and Experimental Analysis of the Effect of Variable Blade Row Spacing in a Subsonic Axial Turbine

Restemeier, M.; Jeschke, Peter; Guendogdu, Yavuz; Gier, Jochen

doi:10.1115/1.4006587

Cited by 17 publications

(5 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In this case, the impact is stronger at blade hub, while tip sections undergo a reduced effect. Walraevens et al and Restemeier et al [6,41] found the same effect in their works.…”

Section: Axial Gap Effect On Stage Performancesupporting

confidence: 54%

“…However, some of the physical mechanisms involved in the variation on axial gap are identified and can be useful for the designer to address the aerodynamic design of the stage. [5,41] in terms of absolute value. They found an efficiency variation of about 0.2-0.3%, even if in these works the position of maximum gain is located at higher axial gap.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Numerical and Experimental Investigation of Axial Gap Variation in High-Pressure Steam Turbine Stages

Bellucci

Rubechini

Arnone

et al. 2017

Journal of Engineering for Gas Turbines and Power

View full text Add to dashboard Cite

This work aims at investigating the impact of axial gap variation on aerodynamic performance of a high-pressure steam turbine stage. Numerical and experimental campaigns were conducted on a 1.5-stage of a reaction steam turbine. This low speed test rig was designed and operated in different operating conditions. Two different configurations were studied in which blades axial gap was varied in a range from 40% to 95% of the blade axial chord. Numerical analyses were carried out by means of three-dimensional, viscous, unsteady simulations, adopting measured inlet/outlet boundary conditions. Two sets of measurements were performed: steady measurements, from one hand, for global performance estimation of the whole turbine, such as efficiency, mass flow, and stage work; steady and unsteady measurements, on the other hand, were performed downstream of rotor row, in order to characterize the flow structures in this region. The fidelity of computational setup was proven by comparing numerical results to measurements. Main performance curves and spanwise distributions have shown a good agreement in terms of both shape of curves/distributions and absolute values. Moreover, the comparison of two-dimensional maps downstream of rotor row has shown similar structures of the flow field. Finally, a comprehensive study of the axial gap effect on stage aerodynamic performance was carried out for four blade spacings (10%, 25%, 40%, and 95% of S1 axial chord) and five aspect ratios (1.0, 1.6, 3, 4, and 5). The results pointed out how unsteady interaction between blade rows affects stage operation, in terms of pressure and flow angle distributions, as well as of secondary flows development. The combined effect of these aspects in determining the stage efficiency is investigated and discussed in detail

show abstract

“…In this case, the impact is stronger at blade hub, while tip sections undergo a reduced effect. Walraevens et al and Restemeier et al [6,41] found the same effect in their works.…”

Section: Axial Gap Effect On Stage Performancesupporting

confidence: 54%

Section: Discussionmentioning

confidence: 99%

Numerical and Experimental Investigation of Axial Gap Variation in High-Pressure Steam Turbine Stages

Bellucci

Rubechini

Arnone

et al. 2017

Journal of Engineering for Gas Turbines and Power

View full text Add to dashboard Cite

show abstract

“…Aerodynamic considerations set the spacing between HPT stator and rotor blade rows. 11,12 The inter-disc spacing is therefore a function of the disc widths which must be limited for both HPT discs to fit. A preliminary sizing of the HPT discs was carried out for both the GIRFC and GISFC concepts.…”

Section: Impact Of Core Configuration On Blade Heightmentioning

confidence: 99%

Concept description and assessment of the main features of a geared intercooled reversed flow core engine

Camilleri

Anselmi

Sethi

et al. 2014

Proceedings of the Institution of Mechanical Engineers, Part G:

View full text Add to dashboard Cite

Intercooled turbofan cycles allow higher overall pressure ratios to be reached which gives rise to improved thermal efficiency. Intercooling also allows core mass flow rate to be reduced which facilitates higher bypass ratios. A new intercooled core concept is proposed in this paper which promises to alleviate limitations identified with previous intercooled turbofan designs. Specifically, these limitations are related to core losses at high overall pressure ratios as well as difficulties with the installation of the intercooler. The main features of the geared intercooled reversed flow core engine are described. These include an intercooled core, a rear-mounted high-pressure spool fitted rearwards of the low-pressure spool as opposed to concentrically as well as a mixed exhaust. In these studies, the geared intercooled reversed flow core engine has been compared with a geared intercooled straight flow core engine with a more conventional core layout. This paper compares the mechanical design of the high-pressure spools and shows how different high-pressure compressor and high-pressure turbine blade heights can affect over-tip leakage losses. In the reversed configuration, the reduction in high-pressure spool mean diameter allows for taller high-pressure compressor and turbine blades to be adopted which reduces over-tip leakage losses. The implication of intercooler sizing and configuration, including the impact of different matrix dimensions, is assessed for the reversed configuration. It was found that a 1-pass intercooler would be more compact although a 2-pass would be less challenging to manufacture. The mixer performance of the reversed configuration was evaluated at different levels of mixing effectiveness. This paper shows that the optimum ratio of total pressure in the mixing plane for the reversed flow core configuration is about 1.02 for a mixing effectiveness of 80%. Lower mixing effectiveness would result in a higher optimum ratio of total pressure in the mixing plane and fan pressure ratio.

show abstract

“…Restemeier et al also conducted similar research on the turbine test (RWTH) of Aachen University. It should also be noted that the smaller stage gap is more conducive to improving the efficiency of turbines with small aspect ratios [13]. Researchers still lack a mature theory of the influence of axial gap changes on turbine flow characteristics [14].…”

Section: Introductionmentioning

confidence: 99%

Numerical and Experimental Investigation on Flow Field of the Turbine Stage under Different Axial Gaps

et al. 2023

View full text Add to dashboard Cite

In order to reduce efficiency losses and improve the aerodynamic efficiency of axial turbines used in industry, the flow fields of the turbine stage were investigated numerically and experimentally under different axial gaps in this work. The influence of the axial gaps on the flow unsteadiness and the flow field distribution is discussed. The results show that the aerodynamic efficiency of the turbine stage increases when the axial distance is reduced. The difference in entropy increases under different axial distances are mainly found in the section from the stator inlet to the rotor inlet: the turbine not only has a better time-average aerodynamic performance, but also has a better transient aerodynamic performance under working conditions with a small axial distance. Additionally, the maximum disturbance amplitudes of the stator and rotor are located near the trailing edge of the stator and the leading edge of the rotor, respectively. Compared with the wake disturbance of the upstream stator to the downstream adjacent rotor, the reverse disturbance of the downstream stator to the adjacent upstream rotor is more sensitive to the change in the blade spacing.

show abstract

Numerical and Experimental Analysis of the Effect of Variable Blade Row Spacing in a Subsonic Axial Turbine

Cited by 17 publications

References 12 publications

Numerical and Experimental Investigation of Axial Gap Variation in High-Pressure Steam Turbine Stages

Numerical and Experimental Investigation of Axial Gap Variation in High-Pressure Steam Turbine Stages

Concept description and assessment of the main features of a geared intercooled reversed flow core engine

Numerical and Experimental Investigation on Flow Field of the Turbine Stage under Different Axial Gaps

Contact Info

Product

Resources

About