Propagation of uncertainty in a rotating pipe mechanism to generate an impinging swirling jet flow for heat transfer from a flat plate

Abstract

In Computational Fluid Dynamics (CFD) studies composed of the coupling of different simulations, the uncertainty in one stage may be propagated to the following stage and affect the accuracy of the prediction. In this paper, a framework for uncertainty quantification in the computational heat transfer by forced convection is applied to the two-step simulation of the mechanical design of a swirling jet flow generated by a rotating pipe (Simulation 1 ) impinging on a flat plate (Simulation 2 ). This is the first probabilistic uncertainty analysis on computational heat transfer by impinging jets in the literature. The conclusion drawn from the analysis of this frequent engineering application is that the simulated system does not exhibit a significant sensitivity to stochastic variations of model input parameters, over the tested uncertainty ranges.Additionally, a set of non-linear regression models for the stochastic velocity and turbulent profiles for the pipe nozzle are created and tested, since impinging jets for heat transfer at Reynolds number of Re = 23000 are very frequent in the literature, but stochastic inlet conditions have never been provided. Numerical results demonstrate a negligible difference in the predicted convective heat transfer with respect to the use of the profiles simulated via CFD. These suggested surrogate models can be directly embedded onto other engineering applications (e.g. arrays of jets, jet flows impinging on plates with different shapes, inlet piping in combustion, chemical mixing, etc.) in which a realistic swirling flow under uncertainty can be of interest.

On the estimation of three-dimensional porosity of insect-proof screens

“…The objective of uncertainty quantification is "to provide confidence measures on how the output of a model is varied due to the variability of its inputs" [44,45]. This field has gained increasing interest in recent years in applications such as complex fluid dynamics [46], ventilation [47], heat transfer [48], or weather forecasting [49],…”

Vortex breakdown mechanics of a laminar confined swirling flow with large expansion ratio using a non-uniform finite difference approximation

“…8,9 Rotating pipes have been recently investigated to generate axisymmetric swirling impinging jets in heat transfer. 29,30 In the simulation of impinging jets the inlet flow is imposed as boundary condition, so the influence of the flow expansion on the inlet conditions can be a point of interest in the field to achieve more accurate simulations. In this sense, this is the most popular and relevant industrial application of sudden expansion jets.…”