Design of micro radial turboexpanders for ORC power cycles: From 0D to 3D

Fiaschi, Daniele; Innocenti, Gianmaria; Manfrida, Giampaolo; Maraschiello, Francesco

doi:10.1016/j.applthermaleng.2015.11.087

Cited by 60 publications

(16 citation statements)

References 13 publications

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“…The maximum turbine isentropic efficiency was 83.5% with a mass flow rate and pressure ratio of 17.24 kg/s and 2.64 respectively. Fiaschi et al [15] carried out 1D design and 3D CFD analysis of the rotor of a micro radial turbine for a small, distributed ORC power system based on R134a as a working fluid. Their comparison between 1D and 3D showed that the maximum difference was 11.6% in terms of power output.…”

Section: Introductionmentioning

confidence: 99%

An innovative small-scale two-stage axial turbine for low-temperature organic Rankine cycle

Jubori

Al-Dadah

Mahmoud

2017

Energy Conversion and Management

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Section: Introductionmentioning

confidence: 99%

An innovative small-scale two-stage axial turbine for low-temperature organic Rankine cycle

Jubori

Al-Dadah

Mahmoud

2017

Energy Conversion and Management

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“…In addition to optimizing the system parameters or working fluids of the ORC cycles, there are a number of studies aimed at improving the efficiency of the ORC components. Redesign and optimization of turbines and pumps are examples of these improvement efforts [43][44][45]. The use of a regenerator and operating in supercritical conditions is also often applied to improve the system performance [46][47][48][49][50][51].…”

Section: Introductionmentioning

confidence: 99%

Exergy Analysis and Performance Improvement of a Subcritical/Supercritical Organic Rankine Cycle (ORC) for Exhaust Gas Waste Heat Recovery in a Biogas Fuelled Combined Heat and Power (CHP) Engine Through the Use of Regeneration

2019

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In the present study, a subcritical and supercritical regenerative organic Rankine cycle (rORC) was designed. The designed rORCs assist a combined heat and power (CHP) engine, the fuel of which is biogas produced from anaerobic digestion of domestic wastes in Belgium. R245fa was selected as the working fluid for both the subcritical and supercritical rORC. During the parametric optimisation, the net power production, mass flow rate, exchanged heat in the regenerator, total pump power consumption, thermal and exergetic efficiencies of rORC were calculated for varying turbine inlet temperatures and pressures. After parametric optimisation of the rORC, the results were compared with the results of the previous study, in which only a simple ORC is analysed and parametrically optimised. Moreover, the effect of the regenerator was revealed by examining all results together. Finally, the exergetic analysis of the best performing subcritical and supercritical rORC was performed. Furthermore, the results of the present and previous studies were considered together and it is clearly seen that the subcritical rORC shows the best performance. Consequently, by using the subcritical rORC, the disadvantages of the using simple ORC (low performance) and supercritical cycle (safety, investment) can be eliminated and system performance can be improved.

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“…On the other hand, achieving high expansion efficiency is particularly challenging: the combined effect of high-pressure ratio (order of 30-50) and low speed of sound characteristic of organic vapors used in hightemperature ORC applications [2] leads to the design of machines with a supersonic radial stator and a transonic mixed-flow rotor, whose design is further complicated by their small dimensions. It follows that the design rules developed for more conventional radial turbines [3][4][5] are arguably inapplicable to this type of expanders, as opposed to mini-ORC radial inflow turbines for low-enthalpy applications [6] or those designed for larger power capacity, which feature moderate expansion ratios, in general not exceeding 12 [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Design Method and Performance Prediction for Radial-Inflow Turbines of High-Temperature Mini-Organic Rankine Cycle Power Systems

Servi

Burigana

Pini

et al. 2019

Journal of Engineering for Gas Turbines and Power

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The realization of commercial mini organic Rankine cycle (ORC) power systems (tens of kW of power output) is currently pursued by means of various research and development activities. The application driving most of the efforts is the waste heat recovery from long-haul truck engines. Obtaining an efficient mini radial inflow turbine, arguably the most suitable type of expander for this application, is particularly challenging, given the small mass flow rate, and the occurrence of nonideal compressible fluid dynamic effects in the stator. Available design methods are currently based on guidelines and loss models developed mainly for turbochargers. The preliminary geometry is subsequently adapted by means of computational fluid-dynamic calculations with codes that are not validated in case of nonideal compressible flows of organic fluids. An experimental 10 kW mini-ORC radial inflow turbine will be realized and tested in the Propulsion and Power Laboratory of the Delft University of Technology, with the aim of providing measurement datasets for the validation of computational fluid dynamics (CFD) tools and the calibration of empirical loss models. The fluid dynamic design and characterization of this machine is reported here. Notably, the turbine is designed using a meanline model in which fluid-dynamic losses are estimated using semi-empirical correlations for conventional radial turbines. The resulting impeller geometry is then optimized using steady-state three-dimensional computational fluid dynamic models and surrogate-based optimization. Finally, a loss breakdown is performed and the results are compared against those obtained by three-dimensional unsteady fluid-dynamic calculations. The outcomes of the study indicate that the optimal layout of mini-ORC turbines significantly differs from that of radial-inflow turbines (RIT) utilized in more traditional applications, confirming the need for experimental campaigns to support the conception of new design practices.

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Design of micro radial turboexpanders for ORC power cycles: From 0D to 3D

Cited by 60 publications

References 13 publications

An innovative small-scale two-stage axial turbine for low-temperature organic Rankine cycle

An innovative small-scale two-stage axial turbine for low-temperature organic Rankine cycle

Exergy Analysis and Performance Improvement of a Subcritical/Supercritical Organic Rankine Cycle (ORC) for Exhaust Gas Waste Heat Recovery in a Biogas Fuelled Combined Heat and Power (CHP) Engine Through the Use of Regeneration

Design Method and Performance Prediction for Radial-Inflow Turbines of High-Temperature Mini-Organic Rankine Cycle Power Systems

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