Experimental characterization and comparison of an axial and a cantilever micro-turbine for small-scale Organic Rankine Cycle

Weiß, Andreas; Popp, Tobias; Müller, J.; Hauer, Josef; Brüggemann, Dieter; Preißinger, Markus

doi:10.1016/j.applthermaleng.2018.05.033

Cited by 60 publications

(23 citation statements)

References 27 publications

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“…Two micro single stage impulse axial turbines with output power of 15 kW and 12 kW were designed and the total-to-static efficiency of 65.0% and 73.4% were obtained, respectively [36]. The maximum isentropic efficiency of the small-scall cantilever turbines also could reach 76.8% [37].…”

Section: Introductionmentioning

confidence: 99%

Preliminary Design of an Axial-Flow Turbine for Small-Scale Supercritical Organic Rankine Cycle

2021

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A small-scale organic Rankine cycle (ORC) with kW-class power output has a wide application prospect in industrial low-grade energy utilization. Increasing the expansion pressure ratio of small-scale ORC is an effective approach to improve the energy efficiency. However, there is a lack of suitable expander for small-scale ORC that can operate with a high efficiency under the condition of large expansion pressure ratio and small mass flow rate. Aiming at the design of high-efficiency axial-flow turbine in small ORC system, this paper investigates the performance of a kW-class axial-flow turbine and proposes a method for efficiency improvement. First, the preliminary design of an axial-flow turbine is conducted to optimize the geometric parameters and aerodynamic parameters. Then, the effects of tip clearance and trailing edge thickness on turbine performance are analyzed under design and off-design conditions. The results show that the efficiency of the two-stage or three-stage turbine is evidently better than that of the single-stage one. The output power and efficiency of the three-stage turbine are close to that of the two-stage turbine while the speed is lower. Meanwhile, the trailing edge loss and leakage loss can be significantly reduced via reducing the trailing edge thickness and tip clearance, and thus the turbine efficiency can be improved significantly. The estimated efficiency arrives at 0.82, which is 33% higher than that of the conventional turbine. Considering the limitation of turbine speed, three-stage axial-flow turbine is a feasible choice to improve turbine efficiency in a small-scale ORC.

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Section: Introductionmentioning

confidence: 99%

Preliminary Design of an Axial-Flow Turbine for Small-Scale Supercritical Organic Rankine Cycle

2021

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“…For electricity generation in such systems, various types of volumetric and dynamic expanders [6] can be used, such as screw expanders, scroll expanders [7], piston expanders [8], vane expanders [9] or turbine expanders [10]. In micro-power ORC systems, microturbines of different types are increasingly used as expanders [10][11][12]. The reasons for this are their small dimensions and many possibilities of designing flow systems.…”

Section: Introductionmentioning

confidence: 99%

Investigation of dynamic properties of the microturbine with a maximum rotational speed of 120 krpm – predictions and experimental tests

Żywica¹,

Kaczmarczyk²,

Breńkacz³

et al. 2020

J. vibroeng.

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Advances in the development of analysis and design methods for fluid-flow machines have enabled both their multi-criteria optimisation and miniaturisation. To decrease the size of such a machine whilst, at the same time, maintaining its output power level, the rotor's rotational speed needs to be increased. It is the reason for serious difficulties with respect to the rotor dynamics and the selection of a bearing system. This article discusses the simulation analysis and experimental research carried out on a prototypical microturbine, designed for use in a domestic ORC (organic Rankine cycle) cogeneration system. During the design process, the basic assumption was to develop a turbomachine, whose dimensions would have been as small as possible and whose output electric power would have been about 1 kilowatt. A supersonic impulse turbine, with a nominal rotational speed of 100,000 rpm, was used in order to obtain high flow efficiency. The maximum speed of the rotor was determined at a level of 120,000 rpm. The article presents the results of analyses made at the design stage and preliminary results of the experimental research. The numerical simulations covered the bearing system optimisation and the rotor dynamics analysis. Next, based on the outcomes of these analyses, a decision was made to use non-conventional gas bearings which are fed by the low-boiling medium's vapour that comes from the ORC system. Within the framework of the experimental research, the dynamic behaviour of the turbogenerator was examined in terms of the rotational speed and produced energy. The performed measurements are proof of very good dynamic properties of the tested machine and after the research was over it was concluded that there were absolutely no signs of wear of the turbogenerator's subassemblies.

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“…They achieved a maximum thermal efficiency of 4.3% and a turbine efficiency of 35% at a rotational speed of 20000 rpm. Weiß et al (2018) conducted an experimental study of the ORC system performance and behaviour depending on the micro impulse turbine and radial cantilever. The measured turbine power output of 12 kW and efficiency of 76.8% was attained with Hexamethyldisiloxane as a working fluid at pressure ratio 22.4 and rotational speed of 27000 rpm.…”

Section: Introductionmentioning

confidence: 99%

Design and manufacturing a small-scale radial-inflow turbine for clean organic Rankine power system

Jubori

Al-Mousawi

Rahbar

et al. 2020

Journal of Cleaner Production

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Experimental characterization and comparison of an axial and a cantilever micro-turbine for small-scale Organic Rankine Cycle

Cited by 60 publications

References 27 publications

Preliminary Design of an Axial-Flow Turbine for Small-Scale Supercritical Organic Rankine Cycle

Preliminary Design of an Axial-Flow Turbine for Small-Scale Supercritical Organic Rankine Cycle

Investigation of dynamic properties of the microturbine with a maximum rotational speed of 120 krpm – predictions and experimental tests

Design and manufacturing a small-scale radial-inflow turbine for clean organic Rankine power system

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