SUMMARY

Digital displays that are deployed in outdoor spaces experience transient temperature and pressure loads due to variations in ambient conditions and internal heat loading. To maintain long term reliability on running units, heat management of electronics and planar control of the LCD cell is required. The balance of pressure distribution and cooling flow can be disrupted due to multiple factors, including leaks from the displays to external surroundings. These leaks cause pressure transients that are observed on fielded displays, which can lead to premature failure of the displays. Understanding the causes and early detection of leaks is key to enhanced reliability and reduced costs of manufacture and maintenance.

This thesis presents a series of experiments and CFD/HT calculations that demonstrate the effects of air leakage through a reduced scale model. This was done through a three-phase approach. The first phase was a series of static pressure tests for leakage rate determination. The second phase used a reduced scale version of an internal flow loop found in displays to replicate pressure transients. The third phase focused on the development of a CFD/HT model as a design aid in the postulation of pressure distribution with leakage effects. The work done in this thesis was primarily experimental, with the CFD/HT model developed as a basis for future work.

By understanding the causes of leakage and resulting pressure signatures, time and costs improvements can be made. With data on gasket leakage rate, the time spent performing quality assurance leak tests can be reduced as a primary benefit. Data from the closed flow loop testing can aid in troubleshooting units with abnormal pressure signatures. The experimental platform itself also provides a relatively quick way to test different design decisions for overall pressure control, while the CFD/HT model is the start for development of more complex scenarios to support it.