Session: 15-02 Swirling Flow / Swirl Chambers

Paper Number: 82198

82198 - The Heat Transfer and Coherent Structures of the Tangential Impingement Jets in the Annular Chamber Studied With Extended Proper Orthogonal Decomposition 

The tangential impingement of turbulent circular jets on the cylindrical surface in the annular chamber is numerically investigated based on the scale-adaptive simulation (SAS). The main purpose is to understand the role of the coherent structures on the temperature field inside the chamber and the heat transfer coefficient field on the hub wall. Based on the jet diameter and inlet velocity of a specific geometric model, the jet Reynolds numbers are given as 285000, 332000, and 392000, respectively. The accuracy of the numerical simulation is verified by the experimental data. The spectrum information of the velocity field is obtained by the fast Fourier transform (FFT) method. An improvement of the proper orthogonal decomposition (POD) method is known as the extended POD (EPOD) method, which is mainly suitable for analyzing the correlations between the flow field and the synchronized scalar or vector fields, such as the correlations between the velocity and the heat transfer coefficient fields. In present study, both the POD method and the EPOD method are applied and compared. The POD method allows to visualize the main modes in terms of velocity and temperature fluctuations. With the help of the EPOD method, the contribution of velocity fluctuations to temperature fluctuations in the chamber and heat transfer fluctuations on the hub wall can be further analyzed. The results of FFT analysis show that there is a dominant frequency of unsteady flow at every jet Reynolds number. As the jet Reynolds number increases, the value of the dominant frequency increases linearly. The fluctuation structures of velocity, temperature, and wall heat transfer coefficient are accurately extracted by the POD method, and the unsteady flow and heat transfer characteristics are obtained. The combined analysis of the POD modes of the heat transfer coefficient on the hub wall and the corresponding EPOD velocity modes inside the chamber provides insights into the physical mechanism of convective heat transfer.

Presenting Author: Lei Shi Shanghai Jiao Tong University

Presenting Author Biography: PhD student at Shanghai Jiaotong University, main research direction: unsteady flow and heat transfer, modal decomposition technique.

Authors:

Lei Shi Shanghai Jiao Tong University
Xiaocheng Zhu Shanghai Jiao Tong University
Zhaohui Du Shanghai Jiao Tong University