Research · Lida Yan

Acoustic sensing of flow condensation

Flow condensation enables efficient heat removal, but its complex interfacial dynamics and corresponding heat transfer are difficult to characterize when optical access and conventional measurements are limited. This work develops an integrated framework for non-intrusive monitoring of flow condensation by combining acoustic emission sensing, signal analysis, and machine learning. Externally mounted sensors capture acoustic signatures of phase change and interfacial dynamics, enabling flow regime identification and quantitative prediction of local vapor quality, heat flux, and heat transfer coefficients. Across steady and transient conditions in horizontal and vertical configurations, the framework connects acoustic measurements with thermal performance, including reconstruction and forecasting with uncertainty estimates, establishing a foundation for real-time diagnostics without optical access or intrusive probes.

Experimental condensation module with externally mounted acoustic sensors

Acoustic emission signals transformed into time-averaged power spectra and labeled with local flow condensation heat transfer measurements

Acoustic spectrograms with and without condensation

Slug-flow acoustic energy peaks and Gaussian mixture-model distributions

Acoustic power spectra compared with images of stratified, transition, and annular flow condensation

Time-domain and frequency-domain acoustic emission features used for flow orientation clustering and orientation-independent heat transfer prediction

Thermal Energy Storage

Dry cooling reduces water consumption in power plants, but its performance declines during hot weather when cooling is most needed. This work explores latent heat enhanced dry cooling to improve cooling performance without additional water consumption. The approach uses salt hydrate phase change materials to store cooling capacity from nighttime air and pre-cool incoming air during the day. Combining molecular dynamics simulations with material development and experimental testing, the project investigates phase change behavior, improves material stability, and integrates encapsulated thermal storage materials into pervious concrete and metal tube modules. Laboratory and prototype evaluations demonstrate sustained air cooling, highlighting the potential of latent heat storage to support more efficient and water-conscious power generation.

Schematic showing nighttime heat rejection from a latent heat storage module and daytime air pre-cooling for an air-cooled condenser

Salt hydrate phase change material additives and measurements of supercooling and latent heat stability

Molecular dynamics simulations of calcium chloride solutions, freezing-point depression, and density

Large-scale dry cooling test duct, metal tube and pervious concrete thermal storage modules, and a chart illustrating air pre-cooling and power-generation benefits

Solid-Gas Multiphase Flow

Heat and mass transfer between solid particles and gases governs the performance of many energy and industrial processes. This research track combines experimental measurements and numerical modeling to understand how particle motion, gas flow, and reactor geometry influence transport and reaction. The work spans spouted-bed processing for mercury removal from coal, steam-enhanced pre-calcination reactor design for cement production, and heat transfer in flowing granular materials. By connecting particle-scale transport with reactor-scale behavior, these studies examine how particle circulation, residence time, and size distribution can guide the design of more efficient thermal and chemical processes.