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This work examines, objectively and subjectively, refrigerant noise induced by the flow of R134a through seven different plate-type automotive evaporator tubes with two tube heights and airflow depths ranging from about 45 mm to 75 mm. Experiments were conducted with both superheated and two-phase refrigerant without and with heating, and without/with lubricant. Measurements of tube surface acceleration were used to quantify flow induced acoustic phenomena. Flow velocity is found to be the critical variable influencing the surface acceleration. Only three types of evaporator tubes consistently whistle above certain threshold velocities. Two other types of tubes produce sporadic, inconsistent whistling, while the remaining two types of tubes never whistle. Half tubes have little influence on acoustic resonance.Adiabatic two-phase flows through a tube never produce resonance.

A traditional method of controlling evaporator superheat in a vapor compression air conditioning system is the thermostatic expansion valve (TXV). Such systems are often used in automotive applications. The TXV depends on superheat to adjust the valve opening. Unfortunately, any amount of superheat causes that evaporator to operate at reduced capacity due to dramatically lower heat transfer coefficients in the superheated region. In addition, oil circulation back to the compressor is impeded. The cold lubricant almost devoid of dissolved refrigerant is quite viscous and clings to the evaporator walls. A system that could control an air conditioner to operate with no superheat would either decrease the size of its existing evaporator while maintaining the same capacity, or potentially increase its capacity with its original evaporator. Also, oil circulation back to the compressor would be improved.

Automotive air conditioning evaporators are known to emit whistling sounds briefly during the startup phase of operation. These sounds have led to customer complaints. Work at the University of Illinois shows that this problem develops when single phase vapor refrigerant flows through the evaporator plate at high velocity. It was further discovered that nitrogen could be used to simulate the phenomenon leading to simpler experimental methods. This paper discusses the development of a technique to use inexpensive rapid prototyping as a tool in the design of new plate evaporators. Some preliminary results along with some limitations of the new technique are discussed.

An existing failure mode identification system requires a user oriented data input facility. This paper describes the development of a graphic's based interface. Generation of the display, the information presented, and user aids are discussed. Attention is then given to portability and enhancements.

This paper describes some strategies for the development of models for material transformations and material failures for use by a rule-based expert system. The advantages and disadvantages of various strategies are discussed.