Heat exchangers remain an integral part of industries to look after heating and cooling requirements. Being an essential device, there has been phenomenal research done to optimize its performance, reduce weight and achieve compactness in the design with same heat transfer capabilities. However, requirements from a particular heat exchanger vary based on its application, requiring customized design features.
The appropriateness of the design and performance evaluation is often a challenging task for engineers, requiring the assistance of mathematical and computational approaches. Although physical tests are significant and most reliable, using the potential of CFD concurrently extends the possibility of developing an optimized heat exchanger design. Below mentioned are some of the prime reasons that will encourage you to utilize CFD in the design process of heat exchangers.
Predicting Flow Patterns
One of the prime factors that decide any heat exchanger’s efficiency is fluid flow interaction with the conducting surfaces. CFD is a powerful tool to visualize flow patterns, identify recirculating zones and flow behavior around restricted areas. These capabilities to capture flow physics allows identification of pressure drops and temperature distribution in the system, which are essentially deciding factors for HE performance.
Determining Heat Transfer Rates
The prime purpose of heat exchanger is to obtain as much cooling or heating as possible depending on its application. With CFD simulation, heat transfer rates can be easily evaluated, which can be further manipulated by modifying the design for performance enhancement. Predicting the heat transfer rates early in the design phase allows better understanding the importance of HE materials. This promotes the use of alternative materials with better thermal conductivity to obtain better heat transfer rates.
Measuring Thermal Stresses and Deformation
Heat exchangers are also designed considering fatigue factors that may fail or degrade the efficiency prior to its actual design life-cycle. It is certain that high temperature fluids develop thermal stresses on the heat exchanging surface, which may lead to excessive deformation followed by development and growth of cracks. Using conjugate heat transfer techniques, the data obtained from the CFD results can be utilized as an input for thermal-structural analysis using finite element method. This coupling will comprehensively evaluate the performance and life-cycle of the heat exchanger.
Optimizing HE Design
With comprehensive information on fluid behavior, the design of the heat exchanger can be optimized for weight reduction and compactness. Finding suitable flow paths and developing greater heat transfer areas will lead to the development of alternative designs that can fulfill the heat exchanging requirements will less investment in materials.
CFD serves as a vital and an assistive tool for physical validation and certainly reduces the number of physical test trials required. For HE manufacturers, this tool significantly helps in reducing the manufacturing time and subsequently come out with an efficient and competitive product in the market. On the contrary, for existing HE applications, the use of CFD can provide insights on identifying reasons of under performance and actual service life.