Collaborative Research: Development of Diagnostic Tools for High Temperature Fluidized Beds

本研究涉及高温沸腾床诊断工具的设计、开发和校准。采用耐磨热流传感器测量高温沸腾床与浸没表面之间的局部热流密度。将开发一种光学探头来检测高温床中局部存在的气泡。光学探头将用于测量气泡尺寸分布、气泡上升速度和气泡体积分数。在这些装置被开发和校准之后，它们将被用来了解在各种操作条件下高温沸腾床内的传热。由于高硫煤和其他固体燃料的硫排放很容易达到空气质量标准，因此开发高硫煤和其他固体燃料的流态化燃烧工艺受到了极大的关注。沸腾床燃烧器还具有燃料类型灵活性的优势，因为它们可以设计为燃烧几种不同类型的燃料。以往对局部床面传热测量的研究大多局限在接近室温的条件下。提高我们对沸腾床的认识，需要对高温现象进行实验表征。该项目将为实现这一总体目标提供实验装置和数据。

This research addresses the design, development and calibration of diagnostic tools for high temperature fluidized beds. An abrasion- resistant heat flux transducer will be used to measure the local heat flux between a high temperature fluidized bed and an immersed surface. An optical probe will be developed to detect the local presence of bubbles in high temperature beds. The optical probe will be used to measure the bubble size distribution, bubble rise speed, and volumetric bubble fraction. After the devices have been developed and calibrated, they will be used to understand the heat transfer in high temperature fluidized beds under a variety of operating conditions. Considerable attention has been devoted to the development of fluidized bed combustion processes for high sulfur coal and other solid fuels since the sulfur emissions from this technology can easily meet the air quality standards. Fluidized bed combustors also have the advantage of flexibility in regard to fuel type because they can be designed to burn several different types of fuels. Most of the previous studies of instantaneous local bed-to-surface heat transfer measurements are restricted to near room temperature conditions. The advancement of our understanding of fluidized beds requires the experimental characterization of the high temperature phenomena. This project will provide the experimental devices and data to meet this overall objective.