Introduction

Dixon, Simon

doi:10.1016/b978-1-85617-793-1.00001-8

Cited by 25 publications

(34 citation statements)

References 2 publications

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“…It can be concluded that the analysis of the response surface is an effective alternative to the conventional orthogonal sensitivity analysis, for the ranking of the impact of the design parameters on the quantity of interest. Table 3 shows the constraints employed in the exemplary design optimization of a 10 kW turbine operating in a cycle with an evaporating temperature of 240 C. These restrictions originate from know-how on the design of radial inflow turbines [33], and from considerations on manufacturing capabilities regarding the minimum blade height.…”

Section: Relevant Design Variables: Response Surface Interpretationmentioning

confidence: 99%

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Active subspaces for the optimal meanline design of unconventional turbomachinery

Bahamonde

Pini

Servi

et al. 2017

Applied Thermal Engineering

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h i g h l i g h t sA reduced-order model is proposed for the design of unconventional turbomachinery. The surrogate combines fluid selection, cycle configuration, and turbine geometry. The surrogate outperforms the standard model with negligible computational cost. The new response surface reveals the dominant inputs for turbine performance. The preliminary fluid dynamic design of turbomachinery operating with non-standard working fluids and unusual operating conditions and specifications can be very challenging because of the lack of know-how and guidelines. Examples are the design of turbomachinery for small-capacity organic Rankine cycle and supercritical CO 2 cycle power plants, whereby the efficiency of turbomachinery components has also a strong influence on the net conversion efficiency of the system. These machines operate with the fluid in thermodynamic states which, for part of the process, largely deviate from those obeying to the ideal gas law. This in turn implies the presence of so-called non-ideal compressible fluid dynamics effects. a r t i c l e i n f oActive subspaces, a model reduction technique, is at the basis of the methodology presented here, which is aimed at the optimal meanline design of unconventional turbomachinery. The resulting surrogate model depends on a very small set of non-physical variables, called active variables. The procedure integrates into a single constrained optimization framework the selection of the working fluid, the thermodynamic cycle calculation and the preliminary sizing of the turbomachinery component.As a demonstration of the advantages of the proposed approach, the design of a 10 kW mini organic Rankine cycle turbine with a turbine inlet temperature of 240 C is illustrated. In this case, approximately the same maximum efficiency is estimated for three dissimilar turbines operating with different working fluids and rather different thermodynamic cycles. The use of active subspaces allows the seamless evaluation of the sensitivity of results to input parameters, both those related to the machine and the working fluid. The novel design procedure is compared in terms of computational efficiency to a conventional approach based on the coupling of a genetic algorithm directly with a meanline code. Results show that the calculation based on the use of surrogate models is more than two orders of magnitude faster. The surrogate can be used to solve any design problem within the specified boundaries of the design envelope. Results are affected by uncertainty on the estimation of losses and of non-ideal compressible fluid dynamics effects, which, in turn, do not affect the applicability of the method, which will become quantitatively accurate once this information will be available. Work to this end is underway in various laboratories.

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Section: Relevant Design Variables: Response Surface Interpretationmentioning

confidence: 99%

“…Finally, an optimal rotor inlet diameter is estimated by means of conventional design guidelines for radial inflow turbines [33], combined with a mass balance assuming an isentropic expansion, which gives…”

Section: Normalized Input Of the Turbine Model For Preliminary Designmentioning

confidence: 99%

Active subspaces for the optimal meanline design of unconventional turbomachinery

Bahamonde

Pini

Servi

et al. 2017

Applied Thermal Engineering

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“…Here, the flow deviation angles at design and off-design points are calculated by McKenzie's and modified Creveling's correlations [1,4]. The present pressure loss models are used to calculate overall total pressure loss coefficient (ω T ) and then actual the total pressure at blade outlet (p 02,actual ) in equations (6), which is required for determining the entropy function, Q, in equation (4).…”

Section: Fan Performance Prediction Methodsmentioning

confidence: 99%

“…Free vortex design concept has been widely used in fan design practice but has the fundamental shortcomings of severe blade twisting causing fan performance deterioration [1]. For this reason, combined vortex design concept is recently being applied for reducing blade twisting as well as improving performance.…”

Section: Introductionmentioning

confidence: 99%

Energy-Saving technology of axial flow fan used in air-conditioning system

Lee¹,

Kim²,

Yeo³

2017

SGCE

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The present study provides an energy-saving design method of axial flow fan used in air-conditioning system and verifies its design results through comparison with test results. The present design method employs combined vortex design concept in constructing three dimensional fan blades, and the performance analysis of designed fan is made by the through-flow method with pressure loss and flow deviation distribution models along swept blade height. For the verification of the present design method, a new fan model is designed and manufactured, and its performances are predicted and compared with actual test results. The comparisons between the present prediction and the test results show very good agreements in the aspects of static pressure, power and efficiency. Furthermore, the present design method is shown to give less power consumption than conventional fan model. 

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“…The basic input parameters for the cryogenic expansion turbine system are: The ratio of exit tip diameter to inlet diameter should be limited to a maximum value of 0.70 (Dixon, 1978;Rohlik and Harold, 1968) to avoid excessive shroud curvature. Corresponding to the peak efficiency point (Balje, 1981):…”

Section: Basic Design Of Turbine Wheelmentioning

confidence: 99%

A computational approach to the design of a cryogenic turbine blade profile

Ghosh¹,

Sahoo²,

Sarangi³

2010

Int. J. Eng. Sci. Tech

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The present day cryogenic gas turbines are in high use as they meet the growing needs for low pressure cycles. This calls for improved methods of blade profile design. The present study is aimed at the design of the blade profile of mixed flow impellers with radial entry and axial discharge. In this paper, details of a computer code have been developed for designing such blade profile. The computational procedure developed describes the three-dimensional contours of the blades for the turbine wheel. The flow of fluid in a turbine blade passage depends on the length of the flow path and the curvature of such path. This has been given due weightage. Effect of some of the turbine operating and design parameters on the flow path and its curvature have been analyzed and presented. Optimum solution for some of the free parameters and angles between velocity components was found. On that basis, co-ordinates of this blade profile were computed. Although manufacturers design the blade profiles for their production, till date no academic literature is available for this purpose. The work may help researchers for further developmental work on this topic as well as the manufacturers of cryogenic expanders.

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Introduction

Cited by 25 publications

References 2 publications

Active subspaces for the optimal meanline design of unconventional turbomachinery

Active subspaces for the optimal meanline design of unconventional turbomachinery

Energy-Saving technology of axial flow fan used in air-conditioning system

A computational approach to the design of a cryogenic turbine blade profile

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