Compositional and entropy indirect noise generated in subsonic non-isentropic nozzles

Domenico, Francesca De; Rolland, Erwan O.; Rodrigues, Jocelino; Magri, Luca; Hochgreb, Simone

doi:10.1017/jfm.2020.916

Cited by 16 publications

(28 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…( 26)). In keeping with the earlier current results and previous investigations [20,33,57], this figure shows that the entropic wave is more strongly annihilated at higher frequencies. It also reveals that the compositional sources are highly affected by the flow thermo-hydrodynamics at high frequencies.…”

supporting

confidence: 92%

“…These traces show that, as expected, during the advection process, the wave amplitude decreases, while the width increases. This is evidence for the wave dissipation and deformation, resulted from turbulence mixing and diffusion [35,53]. The strongest elongation of the waves is observed in the first half of the channel, while the amplitude decrement gradually continues until the outlet.…”

Section: Wall Conditionsmentioning

confidence: 86%

“…In an experimental effort, Rolland et al [22] investigated entropic and compositional waves, and argued that dispersion and diffusion had a minor effect on the waves' deformation. By extending an earlier model presented by Domenico et al [52], it was declared that the compact-nozzle theory might overestimate the compositional noise [53]. They showed that the assumption of an isentropic nozzle could lead to inaccurate predictions and indicated that the compositional perturbation might experience minimal dispersion in short tubes.…”

Section: Nomenclaturementioning

confidence: 86%

“…However, so far, there is no systematic investigation focused on the decay of compositional waves. Existing studies of compositional noise have speculated rather differently about the evolution of these waves [22,[57][58][59] and a conclusive view is yet to emerge. The current work aims to address this issue through conduction of high fidelity numerical simulations of the propagation process of a compositional wave in turbulent channel flows.…”

Section: Nomenclaturementioning

confidence: 99%

See 3 more Smart Citations

A comparative analysis of the evolution of compositional and entropy waves in turbulent channel flows

et al. 2022

View full text Add to dashboard Cite

Indirect combustion noise, as an important source of noise in gas turbines, was traditionally attributed solely to entropy waves. In recent years, compositional waves were introduced as another contributor to indirect combustion noise. Nonetheless, unlike that of entropy waves, the annihilation of compositional waves by the mean flow has remained largely unexplored. Hence, the current numerical study analyses the spatiotemporal evolution of different components of compositional waves and compares them with the decay of entropy waves. A convecting wave, including a mixture of combustion products at elevated temperature, is introduced at the inlet of a simple channel. This allows simultaneous analysis of entropy and compositional waves. The passage of these along the channel is modeled using a large eddy simulation and the annihilation of the waves' components is examined in the frequency domain. It is shown that the turbulence level of the mean flow and convective heat transfer on the walls can both result in a considerable wave deterioration.However, the effects of heat losses from the channel walls are found to be stronger than that of turbulence intensity. Importantly, as the wave is convected, the chemical potential function remains coherent for most of the channel length and deterioration of the compositional wave majorly ensues from the mixture fraction gradient. The results indicate that, overall, the compositional sources feature 10% to 20% more dissipation in comparison with the entropic sources. Therefore, compositional waves are less likely to survive the flow and generate noise.

show abstract

supporting

confidence: 92%

Section: Wall Conditionsmentioning

confidence: 86%

Section: Nomenclaturementioning

confidence: 86%

Section: Nomenclaturementioning

confidence: 99%

See 2 more Smart Citations

A comparative analysis of the evolution of compositional and entropy waves in turbulent channel flows

et al. 2022

View full text Add to dashboard Cite

show abstract

“…However, many practical applications require solutions for non-isentropic mean flows. For instance, De Domenico et al (2021) and Yang, Guzmán-Iñigo & Morgans (2020) recently showed that, in the diverging portion of realistic nozzles, the flow can separate creating recirculation regions and, hence, turbulence both leading to mean flow non-isentropicity and strong deviations from isentropic acoustic theories. Another source of non-isentropicity can be heat transfer, as happens in combustors and heat exchangers.…”

Section: Introductionmentioning

confidence: 99%

A solution for the quasi-one-dimensional linearised Euler equations with heat transfer

2022

View full text Add to dashboard Cite

The unsteady response of nozzles with steady heat transfer forced by acoustic and/or entropy waves is modelled. The approach is based on the quasi-one-dimensional linearised Euler equations. The equations are cast in terms of three variables, namely the dimensionless mass, stagnation temperature and entropy fluctuations, which are invariants of the system at zero frequency and with no heat transfer. The resulting first-order system of differential equations is then solved using the Magnus expansion method, where the perturbation parameters are the normalised frequency and the volumetric heat transfer. In this work, a measure of the flow non-isentropicity (in this case the steady heat transfer) is used for the first time as an expansion parameter. The solution method was applied to a converging–diverging nozzle with constant heat transfer for both subcritical and supercritical flow cases, showing good agreement with numerical predictions. It was observed that the acoustic and entropy transfer functions of the nozzle strongly depend on the frequency and heat transfer.

show abstract

An Arbitrary Lagrangian–Eulerian framework for the consistent analysis of entropy wave generation

Merk,

Eder,

Polifke

2024

Combustion and Flame

View full text Add to dashboard Cite

Compositional and entropy indirect noise generated in subsonic non-isentropic nozzles

Abstract: Abstract

Cited by 16 publications

References 36 publications

A comparative analysis of the evolution of compositional and entropy waves in turbulent channel flows

A comparative analysis of the evolution of compositional and entropy waves in turbulent channel flows

A solution for the quasi-one-dimensional linearised Euler equations with heat transfer

An Arbitrary Lagrangian–Eulerian framework for the consistent analysis of entropy wave generation

Contact Info

Product

Resources

About