Numerical Study of Oscillatory Flow and Heat Transfer in a Loaded Thermoacoustic Stack

Worlikar, Aniruddha S.

doi:10.1080/104077899275362

Cited by 41 publications

(24 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The optimal heat exchanger length (L opt ) was found in between 0.05 -0.25 times (2ξ a + δ κ ), based on the assumptions made for the numerical scheme. This is somewhat smaller than what has been suggested [3,16].…”

Section: Resultscontrasting

confidence: 38%

“…Worlikar and Knio [3], Besnoin and Knio [4], and Marx and Blanc-Benon [5] numerically investigated the effect of a number of relevant parameters on the heat transfer from heat exchangers made of plate fins in oscillatory flows. These parameters in non-dimensional form include the heat exchanger length, the fin spacing and the gap between heat exchangers and plate stacks.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Thermal performance of finned-tube thermoacoustic heat exchangers in oscillatory flow conditions

Kamsanam

Mao

Jaworski

2016

International Journal of Thermal Sciences

View full text Add to dashboard Cite

Heat exchangers play a key role in the overall performance of thermoacoustic devices. Due to the complex nature of oscillatory flows, the underlying mechanism of heat transfer in oscillatory flows is still not fully understood. This work investigates the effect of fin length and fin spacing on the thermal performance of finned-tube heat exchangers. The heat transfer rate between two finned-tube heat exchangers arranged side-by-side in an oscillatory flow was measured over a range of testing conditions. The results are presented in terms of heat transfer coefficient and heat transfer effectiveness. Comparisons are made between experimental results of this work and a number of models, such as, the Time-Average Steady-Flow Equivalent (TASFE) model, the Root Mean Square Reynolds Number (RMS-Re) model and the boundary layer conduction model, as well as several empirical correlations in literature. A new empirical correlation is proposed to be used for the prediction of thermal performance for finned-tube heat exchangers in oscillatory flows. The uncertainties associated with the measurement of heat flux are estimated.

show abstract

Section: Resultscontrasting

confidence: 38%

Section: Introductionmentioning

confidence: 99%

Thermal performance of finned-tube thermoacoustic heat exchangers in oscillatory flow conditions

Kamsanam

Mao

Jaworski

2016

International Journal of Thermal Sciences

View full text Add to dashboard Cite

show abstract

“…This situation can be modeled in the obtained form function Eqs. (24)(25)(26) by setting the thermal and viscous penetration depths at zero value, δ ν = δ κ = 0. Resolving these equations gives the corresponding section average form functions, f…”

Section: Perfect Fluid Casementioning

confidence: 99%

“…In fact, more adequate computational fluid dynamic methods are used to solve unsteady compressible Navier-Stokes equations or the low Mach equivalent equations [3,5,8,10,11,24]. Alternatively, simpler methods are also used and are in good agreement with experiments [12,17].…”

Section: Introductionmentioning

confidence: 97%

Generalization of the thermoacoustic form functions for evaluating the transverse temperature gradient effect

2015

View full text Add to dashboard Cite

Section average of the viscous form function F 0 for perfect fluid g i (0) Section average of the ith thermal form function G i for perfect fluid G i Thermal form functions g i Section average of the viscous form function G i h n Helmholtz number express the ratio l * / * r between the length of channel and the scale of the acoustic wave length * r = 2π ω * r C * r using the scales C * r and ω * r for speed of sound and for angular frequency respectively MaMach number expressing the ratio formed by scales of fluid speed u * r and speed of sound C * r q i Dimensionless heat flux density respectively following the axial and transversal direction i = 1 or 2 q y0 0th order heat flux density following the transverse directionDimensionless coordinate of y * = d * y using length scale d * Y| 0 , Y| 1 Scaled variable of fluid at the interface Γ 1 and Γ 2where or 1 is the order of the variable Y according to Mach number Greek letters δ κScaled thermal penetration depth defined as in literature [7,21], according the length scale d * AbstractThe main purpose of this paper is to study analytically the effect of transverse gradient of time averaged temperature on the oscillating flow between parallel plates that occurs in thermoacoustic device such as resonator, stack and heat exchanger. In fact, this transverse gradient of temperature is not taken into account in standard linear theory and can have considerable consequences on the thermoacoustic machines operating as the onset parameters. For this purpose, an asymptotic model generalizing the standard linear theory is proposed. This approach is done without making supplementary assumptions compared to the known model in literature. Consequently, generalized viscous and thermal form functions are deduced by analytical development. Hence, the results of the thermal nonuniformity according to transverse direction are analyzed using these form functions. Furthermore, the critical temperature gradient is calculated analytically for this case.

show abstract

“…Figure 1 (center) indicates, e.g., the small scale strongly vortical flow that will develop near the end of the plate stack. See [30][31][32][33] for discussions of appropriate numerical techniques for the simulation of such thermoacoustic devices and for extensive numerical results.…”

Section: Thermoacoustic Refrigeratormentioning

confidence: 99%

Multiple spatial scales in engineering and atmospheric low Mach number flows

Klein

2005

ESAIM: M2AN

View full text Add to dashboard Cite

Abstract. The first part of this paper reviews the single time scale/multiple length scale low Mach number asymptotic analysis by Klein (1995Klein ( , 2004. This theory explicitly reveals the interaction of small scale, quasi-incompressible variable density flows with long wave linear acoustic modes through baroclinic vorticity generation and asymptotic accumulation of large scale energy fluxes. The theory is motivated by examples from thermoacoustics and combustion. In an almost obvious way specializations of this theory to a single spatial scale reproduce automatically the zero Mach number variable density flow equations for the small scales, and the linear acoustic equations with spatially varying speed of sound for the large scales. Following the same line of thought we show how a large number of wellknown simplified equations of theoretical meteorology can be derived in a unified fashion directly from the three-dimensional compressible flow equations through systematic (low Mach number) asymptotics. Atmospheric flows are, however, characterized by several singular perturbation parameters that appear in addition to the Mach number, and that are defined independently of any particular length or time scale associated with some specific flow phenomenon. These are the ratio of the centripetal acceleration due to the earth's rotation vs. the acceleration of gravity, and the ratio of the sound speed vs. the rotational velocity of points on the equator. To systematically incorporate these parameters in an asymptotic approach, we couple them with the square root of the Mach number in a particular distinguished so that we are left with a single small asymptotic expansion parameter, ε. Of course, more familiar parameters, such as the Rossby and Froude numbers may then be expressed in terms of ε as well. Next we consider a very general asymptotic ansatz involving multiple horizontal and vertical as well as multiple time scales. Various restrictions of the general ansatz to only one horizontal, one vertical, and one time scale lead directly to the family of simplified model equations mentioned above. Of course, the main purpose of the general multiple scales ansatz is to provide the means to derive true multiscale models which describe interactions between the various phenomena described by the members of the simplified model family. In this context we will summarize a recent systematic development of multiscale models for the tropics (with Majda).Mathematics Subject Classification. 34E13, 76B99, 76Q05, 86A10.

show abstract

Numerical Study of Oscillatory Flow and Heat Transfer in a Loaded Thermoacoustic Stack

Cited by 41 publications

References 0 publications

Thermal performance of finned-tube thermoacoustic heat exchangers in oscillatory flow conditions

Thermal performance of finned-tube thermoacoustic heat exchangers in oscillatory flow conditions

Generalization of the thermoacoustic form functions for evaluating the transverse temperature gradient effect

Multiple spatial scales in engineering and atmospheric low Mach number flows

Contact Info

Product

Resources

About