國立陽明交通大學 機械工程學系
Topic : 國立交通大學 機械工程學系博士候選人演講
First speaker : 畢楨煥 博士
Topic : Quadrotor Control Using Reinforcement Learning
Date & Location : 2020/04/23 (Thu) 3:30 pm - 5:30 pm
Engineering 5 Building B1 International Conference Hall , Classroom 106,205,210 (工程五館 B1 國際會議廳, 教室106,205,210)
Abstract:
The speech gives a brief introduction of our work on a low-level quadrotor control algorithm using neural networks and model-
free reinforcement learning. Without requiring expert demonstrations, the controller output directly mapped to four
actuators in a simulator and real world environment for hovering and tracking tasks.
Second speaker : Ali Abbas 博士
Topic: Augmentation of Natural Convection Heat Sink via Using Displacement Design
Date & Location : 2020/04/23 (Thu) 3:30 pm - 5:30 pm
Engineering 5 Building B1 International Conference Hall , Classroom 106,205,210 (工程五館 B1 國際會議廳, 教室106,205,210)
Abstract:
Miniaturization of electronic devices demands an effective
thermal management system for efficient cooling. Still, many
electronic industries use natural convection cooling techniques
like plate-fin heat sinks as far as no moving part (noise) and
reliability is concerned. In this study, enhancement upon the
widely used plate fin design is incorporated though
displacements. The effect of providing displacement between
alternate fins of plate-fin heat sink is experimentally and
numerically investigated under natural convection condition.
The effect of fin spacing, length, height, and heat flux on
thermal performance is studied. For the smaller fin pacing,
introducing the fin displacement will delay the merging of
boundary layers, and reduce the length of fully developed
region. The design can also entrain the outside air to flow into
the fin array at the upper portion of heat sink for additional
enhancement. The fin displacement effects are especially
effective for a smaller fin spacing due to the larger fully
developed region prevails. On the other hand, the fin
displacement effect can provide an opposite effect when a very
wide fin spacing is used. Similarly, the increase in the fin length
also enhances the heat transfer performance under the fin
displacement conditions. Yet the effect of fin height on the
thermal performance is small and the effect of heat flux is
negligible. The maximum reduction in the thermal resistance is
56% by adopting the displacement design. A drop in fin
temperature at the upper portion for the displacement design
can lead to a reduction in heat transfer coefficient unless it is
accompanied with the drop in air temperature at the same
region. For the heat sink with 3 mm spacing, 100 mm length
and 0.9 emissivity the ratio of heat transfer by radiation to the
total heat dissipation is 38%, while it declines slightly to 34%
with 30 mm displacement despite the increment in view factor
value. For the fixed volume in space, the heat sink with fin
displacement offers a 30% heat transfer enhancement ratio,
28.7% reduction in total mass, and 27.4 % reduction in surface
area over the conventional heat sinks.