The main-auxiliary combined indirect dry cooling system has attracted attention from the industry in recent years

while few scholars at home and abroad have conducted studies on its flow and heat transfer performances. In order to investigate the transport characteristics of the main-auxiliary combined indirect dry cooling system under different configurations

this paper establishes six physical models of the combined indirect dry cooling systems with the double-layer/single-layer main and auxiliary radiators. And then the cooling performances are analyzed and compared using the commercial software FLUENT. The results show that

the construction has obviously higher impacts on the auxiliary cooling system than the main one

meanwhile the air mass flow rate presents larger difference than the heat rejection; In absence of wind

the main-auxiliary combined cooling system with double-layer heat exchanger arrangement

has better cooling performance than that with the single layer heat exchanger arrangement

and case A possesses the best cooling performance; Under crosswind effects

case C has highest cooling capability of the auxiliary cooling system

while the behavior of its main cooling system should also be considered before the engineering selection. This research may provide some theoretical guidelines for the engineering design and application of the main-auxiliary combined natural draft dry cooling system.