Acoustic signature analysis of a bladeless blower

Tiwari, Ravi Nath; Champ, Carlo Alberto Niccolini Marmont Du Haut; Reggio, Federico; Silvestri, Paolo; Traverso, Alberto; Ferrari, Mario L.

doi:10.1016/j.apacoust.2023.109382

Cited by 7 publications

(4 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A pressure ratio of 1.15-1.25 was measured at 20000 rpm and 30000 rpm, which indicates that the prototype can function as a blower [6]. Additionally, this model was examined experimentally for its acoustic features, comparing against a conventional bladed blower [3]. The vibro-acoustic analysis demonstrated, for the first time, that bladeless devices can significantly outperform bladed devices, having much lower levels of noise emissions.…”

Section: Introductionmentioning

confidence: 91%

“…Such market requirements can be met with Tesla or bladeless technologies [3][4]. There are several advantages to this turbomachinery concept, which include reversible operation, low cost, affordable for use with dirty fluids, and low noise levels compared to conventional devices [3][5] [6][7] [8][9] [10]. A Tesla machine has thin disks mounted on the shaft with gaps or spacers, and this disk assembly (rotor pack) is called the Tesla rotor.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Performance assessment of a reversible Tesla machine

Tiwari,

Traverso,

Reggio

2023

E3S Web Conf.

Self Cite

View full text Add to dashboard Cite

It is well known that bladeless or Tesla turbomachinery, which was invented by Nikola Tesla in 1913, has several distinct features, such as reversibility of operation, which includes expander as well as compressor operation, just by reversing the rotational speed, provided that the statoric channels are purposely designed. Despite their potential application to a variety of fields, such as energy harvesting, automotive, light aircraft, and food processing, especially for low volumetric flows, Tesla machines have not found yet a specific market niche. In fact, at small size, it is estimated that the Tesla machinery does not change performance significantly, while conventional bladed machines are subject to significant efficiency reduction because of mechanical tolerances, thus matching the Tesla relatively low performance. Therefore, Tesla machines can become the fluid machinery of choice for small-size applications, thanks to their competitive performance at that size, simple construction, and reversible operation. A key objective of this paper is to numerically study Tesla devices in both expander and compressor modes with air as the working fluid. As a consequence of the high losses due to rotor and stator interactions, statorless (volute) configurations are investigated here, showing superior performance in both direct and indirect modes of operation. With reference to a laboratory prototype under construction, this paper presents the numerical design results, which predict the peak isentropic efficiencies of 63.5% and 57.5%, for the expander and compressor mode of operation, respectively. Actual prototype is expected to match those performance, apart from leakage and ventilation losses, not included in the numerical analysis.

show abstract

Section: Introductionmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Performance assessment of a reversible Tesla machine

Tiwari,

Traverso,

Reggio

2023

E3S Web Conf.

Self Cite

View full text Add to dashboard Cite

show abstract

“…• Examine the relationship between variations in intensity levels and variations in distance (r). The intensity is proportional to 1/r 2 or can be explicitly written as follows [27]:…”

Section: Comparison and Data Analysismentioning

confidence: 99%

Underwater Acoustic Intensity Analysis using Noise Assisted-MEMD with Varying Distances

Fajarwati,

Feriadi,

Widjiati

2023

Jurnal Teknik Elektro

View full text Add to dashboard Cite

With current developments, underwater communication using acoustic signals is widely used. Many things need to be prepared to support a reliable underwater communication system, such as taking measurements in a test tank to find out the correct measurement configuration. Underwater acoustic intensity measurements, which are detailed in this paper, are performed in the test tank using distance variation schemes. Measurements were made at various distances of 4, 10, 20, and 50 meters from the signal source. The hydrophone that was used has a sensitivity of -180 dB re 1V/µPa. The hydrophone was placed at a depth of 2 meters below the surface of the water in the test tank, which divided the test tank depth in half to ensure that reflections from the bottom and the surface were kept to a minimum. However, the problem is that there are noisy signals at different frequencies. This paper proposes a method using Noise Assisted - Multivariate Empirical Mode Decomposition (NA-MEMD) to decompose the signal and then calculate the sound intensity. The result shows that an increase in the distance between the transmitter and receiver, also causes a change in the intensity with an average change of 0.467 dB/meter. It is concluded that the NA-MEMD approach was shown to be successful in decomposing the intended signal from the noise to equalize the quality of the signal received at different distances, and the correlation between intensity value and change in distance is resilient, with a correlation value of 0.98, indicating a very strong correlation.

show abstract

“…The advantages of the Tesla turbine like resistance to erosion [9], low noise [10], reversibility of the flow [1][2], simple and economic in construction and flexibility in the choice of fluid make it well suited for energy harvesting and small-scale power generation application. In recent times, a renovated interest in Tesla machinery is clearly emerging.…”

Section: Background and Motivationmentioning

confidence: 99%

High-Efficient Bladeless Expander Concept

Renuke,

Reggio,

Traverso

et al. 2023

E3S Web Conf.

Self Cite

View full text Add to dashboard Cite

Tesla bladeless expanders are promising in energy harvesting and small-scale power generation applications due to their lower cost and simplicity in design. Although such expanders exhibit very high rotor efficiency (analytical total to static efficiency ~ 90%), it shows poor performance when coupled with a stator (experimental total to static efficiency ~30%) due to losses present in the stator and stator-rotor interaction. This paper presents the design and experiment of a novel, high-efficient Tesla bladeless expander concept. The concept arises from the loss phenomena in the stator-rotor interaction in conventional bladeless expanders, which are among the main causes of the low performance. This concept is believed to bring the bladeless expanders to the same performances as the traditional ones with vanes, compared to which however the bladeless machines boast greater simplicity, robustness, and the absence of performance decay as the size decreases, competing even in the contexts for traditional turbomachinery. The high-efficient bladeless expander prototype with water as a working fluid is designed and developed, representing the similitude case for a liquid butane heat pump. The available isentropic power across the throttling process in the butane case is 3.3 kW @10000 rpm. The turbine consists of 24 nozzles and 150 disks separated by 0.1 mm spacers. The turbine shaft is connected to the high-speed electric generator. The performance test on the expander is carried out at rotational speeds ranging from 3000 rpm to 6200 rpm and with differential pressure across the expander up to 14 bar. Experimental ventilation loss is characterised and its effect on the performance of the expander is discussed. The preliminary results of the expander under investigation showed satisfactory production of power with an acceptable efficiency range. It is also shown that the present concept is promising and able to address the major i.e., stator-rotor interaction which is the major source of loss in the traditional bladeless expander.

show abstract

Acoustic signature analysis of a bladeless blower

Cited by 7 publications

References 36 publications

Performance assessment of a reversible Tesla machine

Performance assessment of a reversible Tesla machine

Underwater Acoustic Intensity Analysis using Noise Assisted-MEMD with Varying Distances

High-Efficient Bladeless Expander Concept

Contact Info

Product

Resources

About