Direct Contact Condensation Jet in Cross-Flow Using Computational Fluid Dynamics

Abstract

The computational fluid dynamics is an important methodology to study the characteristics of flows in nature and in a number of engineering applications. Modeling nonisothermal flows may be useful to predict the main flow behavior allowing the improvement of equipment and industrial processes. In addition, investigations using computational models may provide key information about the fundamental characteristics of flow, developing theoretical groundwork of physical processes. In the last years, the topic of phase change has been intensively studied using computational fluid dynamics due to the computational and numerical advances reported in the literature. Among several issues related to the phase change topic, direct contact condensation (DCC) is widely studied in the literature since it is part of a number of industrial applications. In the present work, DCC was studied using a mathematical and computational model with an Eulerian approach. The homemade code MFSim was used to run all the computational simulations in the cluster of the Fluid Mechanics Laboratory from the Federal University of Uberlandia (UFU). The computational model was validated and showed results with high accuracy and low differences compared to previous works in the literature. A complex case study of DCC with cross-flow was then studied and the computational model provided accurate results compared to experimental data from the literature. The jet centerline was well represented and the interface dynamic was accurately captured during all the simulation time. The investigation of the velocity field provided information about the deeply transient characteristic of this flow. The v-velocity component presented the more large variations in time since the standard deviation was subjected to a variation of about 45% compared to the temporal average. In addition, the time history of the maximum resultant velocities observed presented magnitude from 29 m/s to 73 m/s. The importance of modeling three-dimensional (3D) effects was confirmed with the relevance of the velocity magnitudes in the third axis component. Therefore, the Eulerian phase change model used in the present study indicated the possibility to model even complex phenomena using an Eulerian approach.