What does a corrugated furnace allow for in terms of boiler design?

A corrugated furnace is designed to facilitate differential expansion and contraction in a boiler system. This type of construction involves using corrugated or shaped metal sections that can flex slightly as temperatures change.

In a boiler, various components expand and contract at different rates when subjected to heating and cooling cycles. The corrugation in the furnace walls allows for some movement without causing damage or stress fractures in the material. This design helps maintain the structural integrity of the boiler, reduces the likelihood of mechanical failure, and enhances the overall efficiency and longevity of the unit.

The other options describe features that are not directly associated with the purpose of a corrugated furnace. For instance, increasing boiler mass or adding to material costs would not provide the specific flexibility and durability advantages that the corrugated design offers. Additionally, while combustion turbulence can affect boiler performance, the primary role of a corrugated furnace relates to managing thermal stresses rather than impacting combustion flow directly. Hence, the correct answer highlights the important function of enabling differential expansion and contraction within the boiler design.