Presence of predominantly large quantity of aromatics (polynuclear) is not desirable in aviation fuel, because it has

Solution(By Examveda Team)

The presence of predominantly large quantities of aromatics (polynuclear) in aviation fuel is undesirable due to several reasons, leading to various negative effects on the fuel's properties and performance. These include:

High pour point: Aromatics can contribute to higher pour points, which can lead to poor flow characteristics at low temperatures, affecting the fuel's ability to flow through fuel systems and into engines during cold weather conditions.

Low smoke point: Aromatics tend to have lower smoke points, which can result in increased smoke production during combustion. This can lead to reduced visibility, increased emissions, and potential operational issues.

Low viscosity index: Aromatics can lower the viscosity index of the fuel, which affects its ability to lubricate and provide proper protection to engine components.

High self-ignition temperature: Aromatics can contribute to a higher self-ignition temperature, making the fuel more prone to autoignition, especially at high temperatures and pressures, which can lead to engine knocking and other performance problems.

Considering these negative effects, the correct answer is Option D: All of the above, as all of these factors contribute to the undesirability of predominantly large quantities of aromatics in aviation fuel.