Numerical investigation of steady-state thermal behavior of an infrared detector cryo chamber

An infrared (IR) detector is simply a transducer of radiant energy, converting radiant energy in the infrared into a measurable form. Since infrared radiation does not rely on visible light, it offers the possibility of seeing in the dark or through obscured conditions, by detecting the infrared energy emitted by objects. One of the prime applications of IR detector systems for military use is in target acquisition and tracking of projectile systems. IR detectors also have great potential in commercial market. Typically, infrared detectors perform best when cooled to cryogenic temperatures in the range of nearly 120 K. However, the necessity to operate in such cryogenic regimes makes the application of IR detectors extremely complex. Further, prior to proceeding on to a full blown transient thermal analysis it is worthwhile to perform a steady state numerical analysis for ascertaining the effect of variation in viz., material, gas conduction coefficient (h), emissivity (e) on the temperature profile along the cryochamber length. This would enable understanding the interaction between the cryochamber and its environment. Hence, the present work focuses on the development of steady state numerical models for thermal analysis of IR cryochamber using MATLAB. The numerical results show that gas conduction coefficient has marked influence on the temperature profile of the cryochamber whereas the emissivity has a weak effect. The experimental validation of numerical results has also been presented.