Abstract: Heat exchangers which, through convection or radiation, are designed to absorb varyingly high energy flow about the circumference of their heat transmission walls. The cross-sectional area of the heat exchanger is subdivided into two or more flow passageways by means of inserts in such a manner, that the temperature differences and thermal stresses in the wall resulting from the high differing energy densities are reduced or even prevented. Achieved hereby is an extensively balanced temperature about the circumference of the heat exchanger wall so as to eliminate injurious thermal stresses.