Harnessing High Speed Flow: Dynamic Models for Air Jet Spinning and Bladeless Turbines

Abstract

High speed flow interactions with rotating bodies play an important role in many applications. This thesis explores two areas in this field, dynamic modeling of fibers in air jet spinning, and the performance predictions of bladeless turbines.

In air jet spinning, individual fibers are twisted and wrapped to form yarn using high speed airflow. This work presents CFD studies of the flow field inside an air jet spinning chamber, coupled with dynamic models for wrap fiber motion. A geometric model based on a completed yarn, a one-dimensional equilibrium model, and a two-dimensional time dependent model were created to predict wrap velocities, combining flow field characteristics to yarn production rates. Experiments using high speed imaging were conducted to validate these models, closing the cycle from simulation to reality.

The bladeless turbine is an emerging concept that uses unique characteristics of supersonic flow to generate torque. Computational simulations were performed to assess the performance of both cylindrical and conical bladeless turbines. The analysis of results includes visualization of shock wave formation, pressure distributions, and power extraction as a function of rotational velocity. Numerical analysis and analytical equations were used to guide the geometry of a turbine suitable for testing in a laboratory environment. Modifications and analysis techniques were proposed to enable real-world testing, including the conical design which simplifies experimental integration.

By developing predictive models, this research advances the understanding of fluid-solid interactions in high speed flows, with direct applications to fiber processing and energy generation.