Twisted symmetry in multiple impingement jets at low Reynolds number

Mehryar, Reza; Giovannini, André

doi:10.1016/j.ijthermalsci.2013.10.005

Cited by 5 publications

(1 citation statement)

References 23 publications

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“…Recently in some papers (San and Chen, 2014;Yamane, et al, 2012;Mehryara andGiovanninib, 2014, Xing andWeigand, 2013), Nusselt number distribution on impinging wall of MIJ is reported,this distribution is of particular interest to researches. Thus we demonstrate the local heat flux on the impinging wall as the heat transfer performance of the MIJ.…”

Section: Fig 8 Contour Of Instantaneous Velocity Magnitudementioning

confidence: 99%

DNS analysis of multiple impinging jets

Koide

Tsujimoto

Shakouchi

et al. 2014

JFST

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] IntroductionImpinging jet is widely used for cooling of industrial applications such as electric device, blades of gas turbine, hot steel and so on, since it possesses high performance of heat transfer rate and is easier to implement into various system. Their characteristics are reviewed by a few notable literatures (Kataoka, 1990 ;Viskanta, 1993). So far, a few or several ten thousand Reynolds number, defined with inlet nozzle diameter, are mainly targeted in laboratory research. However, according to the downsizing of electronic equipments, several one hundred of Re numbers are going to be dealt with (Lee, et al., 2008). Impinging jets are subdivided into three regions, such as free jet region, stagnation region and wall jet region (Viskanta,1993). Their performance of heat transfer on the impinging wall is depending on the Re number, the shape of nozzle, the number of nozzle, the distance between the nozzle and the impinging wall and so on (Viskanta,1993). In particular, although a single impinging jet produces high heat transfer rate around an impinging position on an impinging wall, however the heat transfer performance decays with increasing the distance from the impinging position. Thus in order to overcome the shortcoming of single impinging jet (SIJ), i.e., the occurrence of both inhomogeneous heat distribution on the wall and the narrow heating area, multiple impinging jets (MIJ) are generally introduced in industrial applications. Thus far it is well-known that each jet of MIJ interacts with each other, producing the complex flow field (Geers, Hanjalić, and Tummers, 2006;Weigand and Spring, 2011). In addition, the heat transfer performance is significantly influenced with their interaction. Therefore to realize an optimum heat transfer performance, the influence of geometrical arrangement of jets, i.e., the separation length between jets, the arrangement pattern, should be investigated.Recently significant advances of computer power lead to the realization of fluid phenomena including miniature vortices through the direct numerical simulation (DNS). Under the state of the art, we found the effectiveness of the active control of a round jet for the mixing enhancement (Tsujimoto, et al., 2008). Also DNS of impinging jets are conducted so far (Tsubokura, et al., 2003;Hattori and Nagano, 2004) and highly resolved LES ( large eddy simulation ) (Hadžiabdić, and Hanjalić, 2007) has demonstrated the flow structure and the statistical properties of heat transfer. Hence at present it is capable of investigating systematically the effect of control parameter. AbstractIn order to elucidate the heat and flow characteristics of multiple impinging jet (MIJ), we conduct the DNS (direct numerical simulation) of four round impinging jet arranged at an inflow of flow field. To realize the high accurate computation, the discretization in space is performed with hybrid scheme in which sine or cosine series and 6th order compact scheme are used. For the surrounding boundary condition, in order to reduce the artificial n...

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