Fluid-dynamic design and characterization of a mini-ORC turbine for laboratory experiments

Pini, Matteo; Servi, Carlo De; Burigana, Matteo; Bahamonde, Sebastian; Rubino, Antonio; Vitale, Salvatore; Colonna, Piero

doi:10.1016/j.egypro.2017.09.186

Cited by 22 publications

(9 citation statements)

References 7 publications

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“…Moreover, the maximum turbine volumetric expansion ratio is 60. Although such a value my seem too large for a single-stage RIT, the operation of commercial high-temperature 150 kW ORC turbines (Harinck et al, 2013), and a detailed recent numerical study, describing the design of a 10 kW ORC radial inflow expander, supports this assumption (Pini et al, 2017).…”

Section: Preliminary Design Of the Combined Cyclementioning

confidence: 98%

Hybrid Electric Powertrain for Long-Haul Trucks and Buses: Preliminary Analysis of a New Concept Based on a Combined Cycle Power Plant

Noriega

Servi

Colonna

2020

J. Glob. Power Propuls. Soc.

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The electric hybridization of heavy-duty road vehicles is a promising alternative to reduce the environmental impact of freight and passengers transportation. Employing a micro gas turbine as a prime mover offers several advantages: high power density, fuel flexibility, ultra-low emissions, low vibrations and noise, simplicity and lower maintenance cost. State-of-the-art micro gas turbines feature an efficiency of 30%, which can be increased to 40% by employing a mini organic Rankine cycle system as a bottoming power plant. Such a powertrain could achieve higher efficiency with next-gen micro gas turbines and mini ORC systems, especially with an R&D push of the automotive sector. This paper presents the analysis of a hybrid electric heavy-duty vehicle with a prime mover based on this concept. The best combined cycle system stemming from the design exercise features an estimated peak efficiency of 44%, and a nominal power output of about 150kW. This corresponds to the power demand at cruise condition of a long-haul truck. A series configuration with Lithium-Ion batteries was selected for the hybrid powertrain, for it decouples the prime mover dynamics from the power demand. The benchmark is a vehicle featuring a next generation diesel engine, with a peak efficiency equal to 50%. The results show that the fuel economy can be largely improved by increasing the size of the battery in the hybrid powertrain. Furthermore, employing natural gas in the prime mover of the hybrid vehicle leads to ultra low emissions that are well below the limits set by European and north American regulations. Additionally, the CO2 emissions of the hybrid powertrain are considerably lower than that of the benchmark. The work documented here thus demonstrates the potential of this hybrid powertrain concept, especially in terms of exhaust emissions, as a promising transition technology towards the full electrification of the powertrain.

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Section: Preliminary Design Of the Combined Cyclementioning

confidence: 98%

Hybrid Electric Powertrain for Long-Haul Trucks and Buses: Preliminary Analysis of a New Concept Based on a Combined Cycle Power Plant

Noriega

Servi

Colonna

2020

J. Glob. Power Propuls. Soc.

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“…The resulting analysis helps in the final tweaks of the fluid dynamic design and to achieve optimum performance. The detailed design and optimization techniques can be found in [6][7][8] for understanding the radial turbine performance. The authors in [4,8] compiled a list of advantages of using radial turbines specifically for small-scale units over axial machines listed below:…”

Section: Radial Inflow Turbinesmentioning

confidence: 99%

Expanders for Organic Rankine Cycle Technology

Alshammari¹,

Usman²,

Pesyridis³

2018

Organic Rankine Cycle Technology for Heat Recovery

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The overall power conversion efficiency of organic Rankine cycle (ORC) systems is highly sensitive to the isentropic efficiency of expansion machines. No expansion machine type is universally ideal as every machine has its own advantages and disadvantages and is suitable for a comparatively narrow range of operations of the highest efficiency. Therefore, an optimum selection of an expansion machine type is important for a financially viable ORC implementation. This chapter presents the mode of operation, technical feasibility, and challenges in the application of turbo-expanders (radial inflow, radial outflow, and axial machines) and volumetric expansion machines (scroll, screw, piston, and vane) for use in ORC systems. It can be concluded that different machines are suitable for a different range of power output in commercial applications. In general, volumetric machines are suitable for 50 kWe and below but turbomachines are more suitable for power outputs higher than 50 kWe.

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“…This work benefits from the preliminary investigation of the authors reported in Ref. [14]. The CFD results allow to evaluate the loss breakdown, thus enabling insights into the main loss mechanisms affecting high-temperature mini-ORC radialinflow turbines.…”

Section: Introductionmentioning

confidence: 98%

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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Fluid-dynamic design and characterization of a mini-ORC turbine for laboratory experiments

Cited by 22 publications

References 7 publications

Hybrid Electric Powertrain for Long-Haul Trucks and Buses: Preliminary Analysis of a New Concept Based on a Combined Cycle Power Plant

Hybrid Electric Powertrain for Long-Haul Trucks and Buses: Preliminary Analysis of a New Concept Based on a Combined Cycle Power Plant

Expanders for Organic Rankine Cycle Technology

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

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