A piece of corroded steel plate was found in a submerged ocean vessel. It was estimated that the original area of the plate was 17 in.2 and that approximately 2.1 kg had corroded away during the submersion. Assuming a corrosion penetration rate of 200 mpy for this alloy in seawater, estimate the time of submersion in years. The density of steel is 7.9 g/cm3.

4.8 years

Explanation:

The rate of corrosion (CPR) is defined as the rate at which a metal corrodes in a specific environment. It depends on the environmental condition and the type of metal. It is expressed in inches per year or melts per year. CPR is given by:

Where K is a constant = 534, W is the weight corroded = 2.1 kg = 2.1 × 10⁶mg, A is the area = 17 in², ρ is the density = 7.9 g/cm³

From the CPR equation:

The correct option is;

C. Low refrigerant charge

Explanation:

Where both the low-side and the high-side pressure are low the refrigerant is low which may be as a result of a leak

When there is a low refrigerant charge there will be a larger range over which to compress the refrigerant increasing the work required and thus the heat in the system and the due to insufficient refrigerant, the entire system is under served and the evaporator super-heats due to lack of refrigerant

The liquid-line, the TVX evaporator and compressor will see less fluid flow and hence lesser pressures on the low-side and high-side of the refrigeration system.