Date of Award

Fall 12-16-2021

Access Type

Thesis - Open Access

Degree Name

Master of Science in Aerospace Engineering

Department

Aerospace Engineering

Committee Chair

Bertrand Rollin

First Committee Member

Reda Mankbadi

Second Committee Member

Birce Dikici

Abstract

Cryogenic sprays have many applications in modern engineering. Cooling of electronic equipment subject to high heat flows, surgical ablation of gastrointestinal mucosae or orbital maneuvering are a few examples of their versatility. However, the atomization of a cryogenic liquid is a complex process. During such an event, aerodynamic effects associated with secondary atomization are further affected by thermodynamic flashing. A better understanding of the characteristics of cryogenic sprays is then necessary to allow for improved design and optimization in applications. The overarching objective of this study is to document such characteristics. The numerical simulation was performed over cryogenic nitrogen spray using an Eulerian-Lagrangian approach. In other words, while the gas phase of the flow is treated as a continuum, the nitrogen droplets are tracked individually in a Lagrangian sense. Models for evaporation, atomization, and breakups capture the physical processes experienced by droplets along their pathways. In addition, turbulence in the flow is captured by the k-omega SST model. Simulations performed over a wide range of nozzle inlet pressure suggest that the spray cone angle tends to remain constant. In contrast, the diameter of droplets along the centerline of the spray reduces significantly. Finally, it was noticed that a higher concentration of liquid nitrogen is observed on a target plate as the nozzle inlet pressure increases.

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