Experimental Investigation on a 3 kW Air Tesla Expander With High Speed Generator

Renuke, Avinash; Reggio, federico; Silvestri, Paolo; Traverso, Alberto; Pascenti, Matteo

doi:10.1115/1.0002814v

Cited by 11 publications

(13 citation statements)

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“…Although Tesla turbomachinery is a revolutionary technology, it is not commercially applied to any industrial field due to its low performance. Tesla turbines can reach up to 25% isentropic efficiency according to several experimental studies [3,4], with a peak of 36% [6], which is significantly lower than the theoretical one based on literature. However, Tesla turbomachinery has a variety of advantages such as simple design, low manufacturing cost, and the ability to run either as a turbine or as a compressor with minor changes.…”

Section: Introductionmentioning

confidence: 80%

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Numerical Investigation of Bladeless Compressor on Different Disk Spaces and Diffuser Configurations

Tiwari

Eleftheriou

Ferrari

et al. 2022

Volume 4: Cycle Innovations; Cycle Innovations: Energy Storage

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The cost-effectiveness of turbomachinery is a key aspect within the small-size compressor market. For this reason, Tesla turbomachinery, invented by Nikola Tesla in 1913, could be a good solution, particularly for low volumetric flow applications, where volumetric compressors are usually used. It consists of a bladeless rotor which stands out for its ease of construction and its ability to maintain almost the same performance as size decreases. One of its advantages is that it can run either as a turbine or as a compressor with minor modifications at the stator. The objective of this paper is to investigate a 3kW Tesla compressor, which design was derived from an analogous Tesla expander prototype (59% isentropic efficiency from the numerical study), by conducting a computational fluid dynamic analysis for different disk gaps and diffuser configurations. The potential of the Tesla compressor is shown to be quite promising, with a peak isentropic efficiency estimated at 53%. Although bladeless compressor is a simple turbomachinery device, different parts i.e., diffuser, tip clearance, and volute need to be optimized. Utilizing computational fluid dynamics algorithms, different disk gaps and different diffusers are simulated in order to increase the overall performance of the compressor and understand the flow dynamic behavior behind this technology. The dimensionless Ekman number is used to express the optimum disk space of the compressor rotor. Thus, the overall performance of the Tesla compressor is improved by 5–10% points compared to the initial model. Simultaneously, diffuser optimization strategies are applied and proved that there is a direct impact on the optimum design conditions, improving the pressure ratio at high mass flow rates.

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Section: Introductionmentioning

confidence: 80%

“…This is mainly due to the constant performance of the first as size decreases. Thus, Tesla turbomachinery can be a potential prime mover for Micro Gas Turbines in the range of 200W -3kW [6].…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation of Bladeless Compressor on Different Disk Spaces and Diffuser Configurations

Tiwari

Eleftheriou

Ferrari

et al. 2022

Volume 4: Cycle Innovations; Cycle Innovations: Energy Storage

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show abstract

“…This has also been proved by researchers analytically as well as numerically [6][7][8][9][10][11][12][13][14][15][16][17][18]. However, experimentally the complete Tesla turbine efficiency (stator + rotor) has been found very low (< 35%) [4] [5], but still interesting for energy harvesting, storage, or small ORC [19] applications.…”

Section: Introductionmentioning

confidence: 84%

Experimental investigation of bladeless expander with an incompressible fluid

Renuke

Reggio²,

Pascenti

et al. 2022

J. Phys.: Conf. Ser.

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For small-medium heat pumps and small-scale energy storage (e.g., hydro) and other small-scale applications (up to 10kWe), an economical, reliable, durable, robust, and acceptable performing bladeless expander is an attractive technology. In this article, experiments are performed on a bladeless expander of 1kW design power with water as a working fluid. The complete expansion is in the subcooled liquid phase with an overall pressure drop across the expander in the 2-14 bar range. The water expander is designed as a similitude case study for a butane heat pump, where such a bladeless expander could replace the expansion valve recovering untapped energy from isenthalpic to isentropic expansion. Unlike conventional bladed expanders, the present bladeless expander consists of several co-rotating compact disks, closely spaced and parallelly mounted on the shaft which transmits torque using wall shear forces. The present expander design is an improved version resulting from the detailed loss characterisation done on earlier air expanders. The article begins with the definition of design conditions for water expander starting from the expected butane expansion in the heat pump, fully inside the liquid region. The rotor design of a bladeless expander is outlined using dimensionless parameters that dictate the performance features. The turbine is designed for 1kW of power output and 2kg/s mass flow with an overall pressure drop of 14 bar with a rotational speed of 8000 rpm. The resulting turbine rotor consists of an 80mm disk outer diameter, 120 disks and a 0.1mm gap between them. An experimental test rig employing water as a working fluid is described. Experiments are conducted for overall pressure drop ranging in the 2-14 bar interval, with a maximum rotational speed of 6500 rpm. The performance is recorded with two different stator configurations, having two different throat dimensions for varying mass flow at maximum inlet pressure. Peak total to static efficiency of 30% is obtained with a net power of 670 W at ∼3000 rpm. An experimental ventilation loss (end wall viscous disk friction) is performed with both water and air as working fluids to estimate the power loss. It is found that ventilation loss is the major source of loss in the present turbine prototype with a power loss of 250W@3000 and 1100W@8000 rpm, varying quadratically with rotational speed. It is finally concluded that the expander performance is promising because ventilation losses can be potentially reduced with established strategies used in conventional expanders.

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“…2. Moreover, the HP is also equipped with a Tesla Turbine (TT), installed in parallel with the isenthalpic valve allowing to operate in two possible configurations: the traditional one or the "high-efficiency" one in which the TT expander produces mechanical power increasing the HP COP [3].…”

Section: Fig1 -Savona University Campus 'Envision' Integrated System ...mentioning

confidence: 99%

Dynamic model validation of an innovative NIR-solar faÃ§ade panels-based integrated system

Chiara¹,

Anfosso²,

Gini³

et al. 2022

Preprint

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The goal of this paper is to present a dynamic model of an integrated energy system based on Near-InfraRed façade panels and their validation. The innovative solution has been developed in the framework of the 'ENVISION' European Project funded by the EU H2020 Programme. The whole system integrates the ENVISION façade panels with a mGT, a prototype heat pump, and two thermal storages composing an innovative microgrid. This paper briefly describes the whole system and the model of each component together with the main characteristic equations. The work is mainly focused on the model development and validation of the solar-faced panels' systems and the heat pump and its single components. The model will be used to evaluate the impact of the temperature variation of the warm water produced by the panels over the heat pump performance and responsivity and to define the proper integration strategy. The validation of the solar façade panels model and the HP model has been carried out using experimental data and the results showed that the realized models have reliability of more than 98%.

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Experimental Investigation on a 3 kW Air Tesla Expander With High Speed Generator

Cited by 11 publications

References 0 publications

Numerical Investigation of Bladeless Compressor on Different Disk Spaces and Diffuser Configurations

Numerical Investigation of Bladeless Compressor on Different Disk Spaces and Diffuser Configurations

Experimental investigation of bladeless expander with an incompressible fluid

Dynamic model validation of an innovative NIR-solar faÃ§ade panels-based integrated system

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