Convective Heat Transfer from Realistic Ice Accretion Roughness
Ice accretion effects are mitigated during aircraft design using computer codes such as LEWICE. The characterization of convective heat transfer from surfaces with ice roughness is a significant area for improvement of these codes. Funded through a NASA collaborative agreement, the effort focuses on the measurement of convective heat transfer to flows over surfaces with realistic ice roughness properties. The project consists of three primary tasks: 1) measuring the convective enhancement of constant freestream velocity flows over surfaces with realistic ice roughness, 2) measuring the convection heat transfer of flows interacting with the leading edge of an aircraft wing with realistic ice roughness, and 3) measuring the convective enhancement of stagnating flows over surfaces with realistic ice roughness. The project efforts are supported by collaborative activities at the Icing Research Branch at NASA Glenn to measure ice roughness exhibited by airfoils experiencing short-duration icing events. Secondary efforts of the project involve the evaluation of ice roughness properties from three-dimensional laser scans of iced airfoil surfaces created in the Icing Research Tunnel at NASA Glenn. The ultimate goal of the effort is to implement new correlations or advanced approaches for predicting convective heat transfer from realistic ice roughness distributions in current and future ice accretion codes.
Effects of Flow Separation on Low Pressure Gas Turbine Blades
Flow separation is becoming an increasing problem in highly loaded turbine blades. A gas turbine suction surface simulator has been developed for the Baylor University low speed wind tunnel. A contoured top wall in the test section enables the pressure distribution to be simulated on flat plate that corresponds to actual separated flow conditions. Techniques to stop separation will be studied as well as the impact of separation on heat transfer (using a steady state gold foil liquid crystal technique). Comparison will be made with the CFD code Fluent.
Gas Turbine Impingement Cooling
A new experimental facility developed at Baylor University will enable the study of local heat transfer coefficients beneath impinging jets, a technique used to cool gas turbine blades. This research uses the transient liquid crystal technique. In addition, a two-axis hot-wire anemometer traversing system will be used to map the impinging jet flow field interaction and this will be modeled in the CFD code Fluent.
Mapping Local Heat Transfer in Heat Exchanger Louvered-Fin Arrays
An experimental facility has been developed to model arrays of fins looking at pressure drop and heat transfer with different fin configurations. The experiment uses a transient liquid crystal hue technique coupled with a finite element analysis of the fin to determine the local heat transfer coefficient on the fin surface. Comparisons will be made with water tunnel visualizations and CFD using Fluent. This work is sponsored by Dr. Nicole Okamoto, San Jose State University, and Dr. Ken Van Treuren, Baylor University.
Generating & Documenting the Quality of Free Stream Turbulence and its Impact on Heat Transfer
Using the Baylor University wind tunnel, active and passive turbulence generation grids will be evaluated with down stream measurements of turbulence made using a two axis-hot-wire anemometer. Particular attention will be given to length scales "designing" the turbulence for specific flow conditions.
Mixing and transport processes in turbulent boundary layers
A boundary layer can form when a fluid flows above a solid surface. Boundary layer flows can be found in many applications, from the thin layer above a microprocessor which contains a lot of heat produced by the processor to the large scale layer as vast as the planetary boundary layer above the earth surface. This work is to understand the transport and mixing process of irrotational fluid into rotational fluid in turbulent boundary layer. The purpose is to learn how to improve or hinder transport of heat, mass, or momentum into the boundary layer.
Our lab is interested in the development of new processes and materials, and their implementation into technologies that enhance the sustainability of our current technological civilization, with a particular emphasis on energy conversion processes or those that generate fundamental needs for people from matter streams that are currently thought of as wastes. For example, the design of large-scale energy storage options through advances in electrochemical engineering, or the development of processes to desalinate salt water using solar thermal processes. One of the current processes in the lab is the conversion of low value hydrocarbons (the ones commonly flared from various facilities) into easy to store and transport liquid hydrocarbons (e.g., fuels or polymer precursors).