Articles
Infrared Imaging In Engineering Applications
March 23, 2009
•White Paper: Infrared Imaging In Engineering Applications
By Emily M. Hunt West Texas A&M University
Temperature variations that provide valuable information about heat transfer and fluid phenomena that occur during a mechanical and chemical process stand out clearly in an infrared image. An overview is given for three different mechanical engineering projects currently using infrared imaging to describe high-speed thermal events and provide experimental data for computational models. The first project involves conducting experimental measurements and numerical simulations to investigate the effect of mist on the spray heat transfer and fluid dynamics in the cooling of a cylindrical surface heated to the nucleate boiling temperature range. Infrared imaging (FLIR A40) is used to capture the effect of the spray flow conditions on the droplets transportation process around the heated cylinder. As a comparison to laser ignition behaviors, the next study focuses on impact ignition of nano and micron scale energetic material composites. An impact tester is used to measure ignition of the energetic composites to drop-weight impact. Ignition is determined using highspeed thermal imaging (FLIR SC6000). Results show that the difference in ignition sensitivity between composites is greater with laser than with mechanical ignition and a diffusion mechanism controls mechanical ignition. The overall goal of the third project is to use infrared imaging (FLIR SC6000) to examine the initiation and propagation of heat in explosives. To achieve this goal, infrared imaging is used to accomplish map the temperature field created by heating explosive crystal to observe "hot spot" peaks in the material.
Infrared thermal images quickly highlight problems and reveal conditions undetectable by any other sensor technology. Infrared images can also provide useful data describing the ignition and combustion processes that occur during a heat transfer process such as an explosion. The infrared cameras that will be used are a FLIR SC6000 and a FLIR A40 that features an advanced, uncooled microbolometer focal plane array (FPA) detector technology that allows viewing of temperature variations as small as 0.08°C. The spectral range of the camera is 7.5 to 13 µm, which corresponds to incremental temperature ranges between 0 and 2000°C. Viewing of lower temperature ranges is critical in heat transfer processes because this is where the localized energy develops and heat begins to generate. Spatial resolution of the IR camera is 2 µm, which is on the order of or smaller than the explosive and/or energetic crystals and droplets that will be examined and will allow for direct examination of the energy development. Real-time image acquisition can generate clear images of dynamic objects and high-speed thermal events.
Click Here To Download:•White Paper: Infrared Imaging In Engineering Applications
