**7. Conclusions**

The investigations of the heat exchanger have allowed us to formulate the following conclusions:


The further analysis enables the following conclusions:



The analysis of the obtained results has allowed us to observe the places that are most prone to a stability loss, where a concentration of stresses occurs and to determine possible alternations in the thickness of perforated plates (which would be justified economically).

## **8. References**

184 Heat Exchangers – Basics Design Applications

The analysis of the calculation results has shown that the pipes mounted in the outer part are subject to higher deformations that the pipes mounted inside the central part of the plate

In the general case, a stability loss of the elastic structure is a nonlinear problem that can be investigated with the iterative or incremental analysis of large displacements. This issue was dealt with by Arygyris (1977). With respect to the critical value of load, an influence of geometrical nonlinearity remains insignificant in numerous cases. When it is exceeded, a radical change in the configuration that corresponds to the equilibrium state occurs. If we are interested in the value Pkr and the postcritical state, it is enough to apply an elastic analysis. The task is not so easy in the heat exchanger under investigation. The structure of the device is complex and loaded with pressures that follow from the operation, therefore the FEM calculations were proposed. The investigations of the deformation nature of the heat exchanger and the analysis of strains and displacements are very important tasks which would allow designers to evaluate the correctness of the structure in order to avoid considerable differences in displacements, e.g., through a change in the connection of the perforated bottom with the jacket or an application of a

The conducted here analysis of strains in individual structural elements of the heat exchanger allows researchers to foresee the places of stress concentration. Thus, respective changes can be introduced in order to decrease a number of failures of the

The investigations of the heat exchanger have allowed us to formulate the following








that are subject more to elongation than to deflection.

pipe compensation, etc.

structure.

conclusions:

**7. Conclusions** 

zones either;

(Fig. 22);

stability loss,

geometrical modes of buckling;

the collar ( Fig.6 and Fig.14),

length is of a nonlinear character (Fig.21);

maximal stresses occurring in pipes and the jacket.

The further analysis enables the following conclusions:

Achtelik H., Gasiak G., Grzelak J. (2005). *Strain and load carrying capacity of perforated plates under axial – symmetrical load*, Oficyna Wydawnicza, Opole, Poland [in Polish] User' s Guide ANSYS 12

Bijlaard P.P. (1950). *On the plastic buckling of plates,* J. Aeron. Sci., Vol.17


**Part 2** 

**Micro-Channels and Compact Heat Exchangers** 

