Upcoming ENME Webcasts
LEADERS IN MECHANICAL ENGINEERING LECTURE SERIES - SPRING 2008
Product Design and Decision Making
Lecturer: Deborah Thurston - University of Illinois
Air Date: Friday, May 2nd at 1:30pm
Abstract: Good design requires making difficult decisions. Tradeoffs must be made, often under uncertainty. In contrast to the high level of mathematical rigor that engineers traditionally employ to model physical systems, decision systems are too often ad hoc and arbitrary. This leads to suboptimal designs, or those that are not in the manufacturer's best interests. A decision based approach to engineering design and product development is presented. There are three elements, performed in an iterative manner. The first element is to expand the traditional scope of analysis to include issues such as manufacturing cost, operations, environmental impact, the business model, etc. The second element is to formulate a design optimization problem, articulating an objective function, decision variables and constraints. The third element is a systems analysis of the results of the first two elements. An illustrative overview of two projects is presented, including new product design and development for an air pollution control device, and design for sustainability through product take-back and reuse.
TRANSFORMING ENERGY LECTURE SERIES - SPRING 2008
...Will return in the fall, please check back for more great webcasts!
LEADERS IN MECHANICAL ENGINEERING LECTURE SERIES
Gas-Liquid Interface Deformations in Thin Locally Heated Liquid Films
Lecturer: Yulia Kabova, Russian Academy of Sciences - Novosibirsk, Russia
Air Date: Friday, May 9th at 2:00pm
Abstract: The levels of energy generation in high-speed computer chips are now approaching very high values (up to 100-150 W/cm2), and they are on the edge of exceeding the capabilities of today’s air-cooling technology. Thin liquid films may provide very high heat transfer intensity and may be used for cooling of microelectronic equipment. A particularly promising technological solution, allowing to reach high heat fluxes and to decrease space and mass of cooling equipment, is a set-up where heat is transferred to a thin liquid film driven by a forced gas or vapor flow of the same liquid in a micro or minichannel. Main objective of the present work is to create a mathematical model which allows getting in-depth understanding of the physics of two-phase flow of thin locally heated liquid film driven by gravity and gas flow in a micro- or minichannel under a variety of parametric influences.
Three-dimensional time-dependant mathematical model for calculation of gas-liquid interface deformations and evolution of temperature and velocity fields is developed. Effects of surface tension, temperature dependent viscosity and thermocapillarity are taken into account. Thin layer approximation technique is used.
The effect of mutual location of heaters on a substrate as well as the effect of size of hot spots on 3-D structures, occurring at the film surface, is investigated to define main features of the film dynamics. Calculations are carried out for two equal rectangular heaters arranged in a row (in spanwise or streamwise directions).
The influence of a temperature dependent viscosity on film deformations is investigated. A generalized analytical formula for film thickness as a function of liquid flow-rate is obtained. Criterion for appearance of a second order deformation of the free surface before the bump up to flow is found analytically. For the case of thin nonisothermal liquid film flowing under action of gravity force and co-current gas flow, which create the tangential force on the gas-liquid interface, the effect of gravity as well as the effect of gas speed is studied to define main features of the film dynamics.
TRANSFORMING ENERGY LECTURE SERIES
None at this time.
