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Articles 1 - 10 of 10
Full-Text Articles in Mechanical Engineering
Hybrid Phase-Change Lattice Boltzmann Simulation Of Vapor Condensation On Vertical Subcooled Walls, Wandong Zhao, Yuan Gao, Ruijie Li, Songgang Qiu, Yin Zhang, Ben Xu
Hybrid Phase-Change Lattice Boltzmann Simulation Of Vapor Condensation On Vertical Subcooled Walls, Wandong Zhao, Yuan Gao, Ruijie Li, Songgang Qiu, Yin Zhang, Ben Xu
Mechanical Engineering Faculty Publications and Presentations
Saturated vapor condensation on homogenous and heterogeneous subcooled walls is presented in this study by adopting a hybrid phase-change multiple-relaxation-time Lattice Boltzmann model. The effects of wall wettability on the condensation process, including droplets’ growth, coalescence and falling, and the influence of vapor flow to condensation are investigated. The results demonstrate that the heat fluxes around the triple-phase contact lines are higher than that in other cold areas in homogeneous subcooled walls, which actually indicates the fact that filmwise condensation is preventing the continuous condensation process. Furthermore, the dropwise condensation can be formed more easily on the heterogeneous surface with …
A Parametric Study Of Wave Interaction With A Rotor Having Hydrofoil Blades, Yingchen Yang, Fredrick A. Jenet, Ben Xu, Juan Carlos Garza, Benjamin Tamayo, Yessica Chavez, Oscar Reyes, Samuel Fuentes
A Parametric Study Of Wave Interaction With A Rotor Having Hydrofoil Blades, Yingchen Yang, Fredrick A. Jenet, Ben Xu, Juan Carlos Garza, Benjamin Tamayo, Yessica Chavez, Oscar Reyes, Samuel Fuentes
Mechanical Engineering Faculty Publications and Presentations
Our recent progress on studying wave interaction with a lift-type rotor is discussed in this paper. The particular focus is on characterization of the rotor’s unidirectional responsiveness in waves. The rotor consists of six hydrofoil blades in two sets. One blade set has three blades laid out as a vertical-axis wind turbine of the Darrieus type. The other blade set has three blades configured like a Wells turbine. In combination, the formed rotor can be driven by flows in any direction to perform unidirectional rotation about its vertically mounted shaft. This unidirectional responsiveness of the rotor also holds in waves, …
A Vertical Axis Rotor For Wave Energy Conversion, Yingchen Yang, Joab Soto, Francisco Salazar
A Vertical Axis Rotor For Wave Energy Conversion, Yingchen Yang, Joab Soto, Francisco Salazar
Mechanical Engineering Faculty Publications and Presentations
The present work augments vertical-axis unidirectional wave energy converter (WEC) designs with a new approach. The enabling technique is the hydrodynamic design of a special rotor, which consists of a series of uniquely shaped blades in a certain formation. Specifically, individual blades are realized by revolving a two-dimensional symmetric hydrofoil about its chord line. Then the blades are arranged around a vertical shaft in a desired formation to form the rotor. When driven by an approaching flow through interaction, the rotor naturally rotates about the vertical shaft in a predefined direction. The approaching flow could be from any spatial direction, …
A Vertical Axis Wave Turbine With Hydrofoil Blades, Yingchen Yang, Isaiah Diaz, Sergio Soto Quintero
A Vertical Axis Wave Turbine With Hydrofoil Blades, Yingchen Yang, Isaiah Diaz, Sergio Soto Quintero
Mechanical Engineering Faculty Publications and Presentations
This work discusses a new wave energy converter (WEC) design that, when deployed in waves, performs unidirectional rotation about a vertical shaft. The uniqueness of this new WEC design is on utilizing omnidirectional water flow generated by waves to drive a rotor to perform unidirectional rotation about a vertical axis. This unique feature circumvents the frequency-dependent issue of common WECs, and eliminate realignment needs to cope with dynamically changing wave propagation directions. The key component of the WEC is a rotor, which has a vertical shaft with a number of blades mounted to it. Each blade has a hydrofoil-shaped cross …
A Surface Rejuvenation Model For Turbulent Heat Transfer In Annular Flow With High Prandtl Number, Benjamin Chung, Lindon Thomas, Yi Pang
A Surface Rejuvenation Model For Turbulent Heat Transfer In Annular Flow With High Prandtl Number, Benjamin Chung, Lindon Thomas, Yi Pang
Yi Pang
Heat transfer for high Prandtl number fluids flowing turbulently in a concentric circular tube annulus with prescribed wall heat flux is investigated analytically. This surface rejuvenation based analysis is restricted to thermally and hydrodynamically fully developed flow with constant properties and negligible viscous dissipation. This formulation leads to predictions for the Nusselt Number that are in basic agreement with predictions obtained on the basis of earlier eddy diffusivity models for 30 ≤ Pr ≤ 1000 and 104 ≤ Re ≤ 106 .
Near-Wall Measurements For A Turbulent Impinging Slot Jet System, Jiang Zhe, Vijay Modi
Near-Wall Measurements For A Turbulent Impinging Slot Jet System, Jiang Zhe, Vijay Modi
Dr. Jiang Zhe
The velocity field in the vicinity of a target surface with a turbulent slot jet impinging normally on it is examined. The impingement region is confined by means of a confinement plate that is flush with the slot and parallel to the impingement plate. The distance H of the impingement wall from the slot is varied from 2 to 9.2 slot widths. Jet Reynolds numbers (based on slot width B) of 10,000–30,000 are considered. Mean velocity and root mean square velocity measurements are carried out using hot-wire anemometry. A boundary layer probe is utilized in order to obtain measurements at …
A Microfluidic Mixer Utilizing Electrokinetic Relay Switching And Asymmetric Flow Geometries, Yiou Wang, Jiang Zhe, Prashanta Dutta, Benjamin Chung
A Microfluidic Mixer Utilizing Electrokinetic Relay Switching And Asymmetric Flow Geometries, Yiou Wang, Jiang Zhe, Prashanta Dutta, Benjamin Chung
Dr. Jiang Zhe
No abstract provided.
On Damping And Fluidelastic Instability In A Tube Bundle Subjected To Two-Phase Cross-Flow, Joaquin Moran, David S. Weaver
On Damping And Fluidelastic Instability In A Tube Bundle Subjected To Two-Phase Cross-Flow, Joaquin Moran, David S. Weaver
Publications and Scholarship
An experimental study was conducted to investigate damping and uidelastic instability in tube arrays subjected to twophase cross-ow. The purpose of this research was to improve our understanding of these phenomena and how they are affected by void fraction and ow regime. The working uid used was Freon 11, which better models steam-water than air-water mixtures in terms of vapour-liquid mass ratio as well as permitting phase changes due to pressure uctuations. The damping measurements were obtained by plucking the monitored tube from outside the test section using electromagnets. An exponential function was tted to the tube decay trace, producing …
Damping Measurements In Tube Bundles Subjected To Two-Phase Cross Flow, Joaquin Moran, David S. Weaver
Damping Measurements In Tube Bundles Subjected To Two-Phase Cross Flow, Joaquin Moran, David S. Weaver
Publications and Scholarship
An experimental study was conducted to investigate twophase damping in tube arrays. The objective was to compare different measurement methodologies in order to obtain a more reliable damping estimate. This will allow for improved guidelines related to failures due to fluidelastic instability in tube bundles. The methods compared were the traditionally used halfpower bandwidth, the logarithmic decrement and an exponential fitting to the tube decay response. The working fluid used was Refrigerant 11 (Freon), which better models the real steamwater problem, as it allows for phase change. The void fraction was measured using a gamma densitometer, introducing an improvement over …
Liquid Immersion Cooling Of A Longitudinal Array Of Discrete Heat Sources In Protruding Substrates: Ii—Forced Convection Boiling, Theodore J. Heindel, S. Ramadhyani, F. P. Incropera
Liquid Immersion Cooling Of A Longitudinal Array Of Discrete Heat Sources In Protruding Substrates: Ii—Forced Convection Boiling, Theodore J. Heindel, S. Ramadhyani, F. P. Incropera
Theodore J. Heindel
Forced convection boiling experiments have been performed for an in-line 1 x 10 array of discrete heat sources, flush mounted to protruding substrates located on the bottom wall of a horizontal flow channel. FC-72, a dielectric fluorocarbon liquid, was used as the heat transfer fluid, and the experiments covered a range of flow velocities, degrees of fluid subcooling, and channel heights. The maximum heater-to-heater surface temperature variation was less than 2.5°C and was insensitive to channel height under conditions of fully developed nucleate boiling. Although the fluid velocity influenced the heat flux for partially developed nucleate boiling, its influence was …