Thermische Turbomaschinen

Traupel, Walter

doi:10.1007/978-3-642-96374-2

Cited by 148 publications

(54 citation statements)

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“…For the power generation sub-system, the compressor off-design characteristics were derived by applying a stage-stacking analysis [32][33][34], while the calculations of the isentropic efficiency of each stage were based on the pressure drop assumptions presented in Templalexis et al [35], and the works of Lieblein [36] and of Saravanamuttoo et al [37]. The turbine off-design characteristics were derived following the method described in Stodola [38] and in Traupel [39].…”

Section: System Modelling and Simulationmentioning

confidence: 99%

Life performance of oil and gas platforms: Site integration and thermodynamic evaluation

Nguyen

Fülöp

Breuhaus

et al. 2014

Energy

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Oil and gas platforms are energy-intensive systems, which operate under changing boundary conditions over time. In this paper, the life performance of an offshore platform is analysed by comparing three representative stages of an oil field (early-life, plateau and end-life productions). The energy requirements are assessed by a process integration study, and the system inefficiencies are pinpointed by performing an exergy accounting. The heating and cooling requirements vary significantly over time, and most inefficiencies take place in processes where chemical exergy is consumed ( 50-55 %), thermal exergy is transferred ( 15-20 %), or mechanical exergy is varied ( 10-15 %). These findings are valid for all production periods: this suggests that more attention should be paid on a proper integration of the processing and utility plants, by, for instance, recovering heat from the turbine exhausts and from the exported gas. Multi-objective optimisations are conducted for evaluating the integration of steam and organic Rankine cycles, considering thermodynamic, economic and environmental performance indicators. They indicate that the profitability of a given improvement measure mainly depends on (i) the field properties, (ii) the platform operating strategy, and (iii) the production stage of the oil field. The implementation of steam networks appears promising, as it results in a better performance of the offshore platform and in larger economic profits.

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Section: System Modelling and Simulationmentioning

confidence: 99%

Life performance of oil and gas platforms: Site integration and thermodynamic evaluation

Nguyen

Fülöp

Breuhaus

et al. 2014

Energy

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“…), and several correlations were proposed for each loss type. The results of these investigations have been published in numerous papers and books, with [1][2][3][4][5][6][7][8][9][10] representing the most frequently cited works.…”

Section: Introductionmentioning

confidence: 99%

“…As the coolant is mixed with the main flow, these losses are called mixing losses. The models for these losses are presented in [2,5,[7][8][9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

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Experimental and Numerical Study of Transonic Cooled Turbine Blades

Granovskiy

Грибин

Lomakin

2018

IJTPP

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State-of-the-art gas turbines (GT) operate at high temperatures that exceed the endurance limit of the material, and therefore the turbine components are cooled by the air taken from the compressor. The cooling provides a positive impact on the lifetime of GT but has a negative impact on its performance. In convection-cooled turbine blades the coolant is usually discharged through the trailing edge and leads to limitations on the minimal size of the trailing edge, thereby negatively affecting the losses. Moreover, the injection of cooling air in the turbine disturbs the main flow, and may lead to an additional increase in loss. Trailing edge loss is a significant part of the overall loss in modern gas turbines. This study comprises investigations of the unguided flow angle, the trailing edge shape, and cooling air injection through the trailing edge on the base pressure and profile losses in cooled blades. Some vane and blade cascades with different unguided turning angle and two shapes of trailing edges with and without coolant injection were studied both experimentally and numerically. This analysis provides a split of losses caused by different factors, and offers opportunities for efficiency and lifetime improvements of real engine designs/upgrades. In particular, it is shown that an increase in the unguided turning angle and the use of a round trailing edge result in a reduction of loss in case of a relatively thick trailing edge. Numerical investigation showed that an increase in the unguided turning angle at the initial transonic vane with a thick and blunt trailing edge, without a change in other basic geometric parameters, allowed for a significant reduction of the profile loss by about 3-4% at the exit Mach number M 2is = 0.7-1.0. Experimental investigation of four cascades with cooling air injection into the base flow through the trailing edge allowed us to validate the fact that in blades with a low level of base pressure C pb < −0.1 at m = 0 a non-monotonic dependence of the change of losses against relative cooling air mass flow m is observed. Firstly, the cooling air injection into wake increases base pressure and decreases losses; then the losses start to increase with increasing cooling mass flow due to the interaction between the main flow and the cooling air (mixing losses) and, finally, due to the cooling mass flow increase and momentum increase losses are decreased. In blades with an increased level of the base pressure coefficient C pb ≥ −0.1 at m = 0 the cooling air injection results in an increase in losses right from the beginning of the injection and then, according to the cooling mass flow increase and momentum rise, losses decrease. It is also shown that injection through the trailing edge slot parallel to the main flow leads to a neutral loss impact and even a loss reduction in the subsonic range and a loss increase in the supersonic range of exit Mach numbers.

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“…The averaged quantities must be consistent with conservation laws of thermodynamics and fluid mechanics. The significance of an appropriate averaging technique and its impact on the results has been well known in the turbomachinery community for more than three decades and does not need to be reviewed here (see extensive review by Traupel, 1977). A simple consistent averaging technique that yields consistent results at a plane…”

Section: Figurementioning

confidence: 99%

Aerodynamic and Performance Behavior of a Three‐Stage High Efficiency Turbine at Design and Off‐Design Operating Points

Schobeiri

Gilarranz

Johansen

2004

International Journal of Rotating Machinery

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Address correspondence to M. T. Schobeiri, Texas A&M University, Dept. of Mechanical Engineering, College Station, TX 77843-3123. E-mail: tschobeiri@mengr.tamu.edu the experimental and computational results. The detailed 3-D flow pictures delivered by viscous flow solvers display the source and location of the total pressure losses and entropy distribution within the blade channel, particularly at the blade hub and tip regions. Based on these results, the turbine aerodynamicist is able to reconfigure the blade geometry to reduce the profile and the secondary flow losses. The latter is especially relevant for high pressure (HP) turbine design with relatively small aspect ratios where the secondary flow losses significantly contribute to the reduction of the stage efficiency. In recent years, the power generation turbine manufacturers have been increasingly focusing their efforts on reducing the secondary flow losses of HPturbine blades by implementing the information obtained from the Navier-Stokes flow simulations. To account for the discrepancy mentioned above, the Navier-Stokes codes are frequently calibrated. The calibration process may provide a temporary matching solution for cases in which experimental results are available. However, it is not appropriate for a priori predicting of the efficiency of new designs. The disagreement between the Navier-Stokes based efficiency calculations and the measurements, however, does not allow the engine manufacturer to issue efficiency and performance guaranty without thoroughly testing their new design. Considering the physical aspects of the computation, among other things, two major issues may be considered primarily responsible for the above discrepancy, namely the turbulence modeling and the modeling of the laminar-turbulent boundary layer transition process. The latter directly impacts the accuracy of the loss, efficiency and heat transfer calculations of the blade and thus the turbomachinery stage. BACKGROUND: UNSTEADY BOUNDARY LAYER TRANSITIONTo quantify the effect of unsteady boundary layer transition on turbine efficiency the first author initiated a comprehensive unsteady boundary layer research program at Texas A&M University, where he and his co-workers studied the development

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Thermische Turbomaschinen

Cited by 148 publications

References 0 publications

Life performance of oil and gas platforms: Site integration and thermodynamic evaluation

Life performance of oil and gas platforms: Site integration and thermodynamic evaluation

Experimental and Numerical Study of Transonic Cooled Turbine Blades

Aerodynamic and Performance Behavior of a Three‐Stage High Efficiency Turbine at Design and Off‐Design Operating Points

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