Eliminating Hot Spots Using Computer Aided Engineering

Most engineering products involve their application under extreme thermal environments

Examples could range from electronic components such as microprocessors to mechanical devices such as turbines, compressors and engines.

All these devices are exposed to high temperatures, causing possible damage due to thermal stresses and subsequent deformation.

One of the prime concerns for design engineers in such cases is to avoid building up of thermal concentrated regions often referred to as hot-spots.

Moreover, with increasing requirement from the market to build compact products, the situation is even more challenging to engineers in designing products that remain thermally uniform during their applications.

A hot spot can be imagined in a thermally sensitive product such as a heat exchanger utilized in industrial applications. The purpose of heat exchanger is to absorb heat from the motive hot fluid by the use of a secondary cold fluid such as refrigerant. The process of heat exchange usually takes place using indirect cooling or heating by allowing both the fluids to flow separately in tubes closed in contact with each other.

The effectiveness of heat exchanger depends on uniform heat transfer from one fluid to the other across the HE geometry. A hot spot problem can also be realized in data centers where high processing computing servers generate lot of heat, which is required to be removed, or else the electronic component might fail.

Evaluating the hot spot experimentally is quite time consuming and requires complex physical setup. Despite setting up physical model, it is quite complicated to study the behavior of the flow at every instant and at every region. It also becomes difficult for manufacturers to invest extra time and cost in performing experimental investigations in a market scenario where faster product placement is a must.

The use of computer aided engineering proves to be extremely beneficial in visualizing the effects of high temperature in the product design and determine hot spots, without building prototypes. The numerical techniques employed in computational fluid dynamics can help in solving fluid flow equations across the specified domain, providing insights about the fluid behavior and interaction with the solid surfaces.

Finite element analysis on the other hand can be used to study the heat flow in solids using heat conduction equations.

The use of computer aided engineering provides information about things that cannot be seen visually. In case of a data center, the air flow inside the room can be simulated using fluid flow and heat transfer equations across the domain by sub-dividing into number of smaller elements. This technique helps in determining the flow parameters more precisely at each region.

Critical regions in the data center can be identified where the air flow is not sufficient, promoting hot spots. The results can help in optimizing the design of the HVAC system or placement of the servers to achieve optimum cooling.

Thermal analysis in solids using FEA can help in visualizing the stresses and deformation developed in the product such as an engine piston. The results also help in identifying high stress concentration regions or hot spots, which can be eliminated through design optimization without physical trials.

Hot spots are critical for any engineering product involving the interaction of thermal conditions. While in many cases the effect of hot spots may be realized after a prolonged exposure, there may be instances where the product might fail with short period of its service. In any case, eliminating the hot spot is a prime requirement for engineers, and utilizing the power of CAE can significantly assist in the elimination process.