To solve the prominent problem of convective heat transfer enhancement in solar collector tubes

experimental investigation on enhancing heat transfer between tube well and medium by copper inserts with double multiple spiral coils and three multiple spiral coils was conducted

by using field synergy theory.The results show that

the convective field synergy number Fc increases sharply with the synergy angle cosine cosβin the multiple spiral coils tubes.Moreover

the velocity field and temperature field also show a good cooperativity.The working fluid with three spiral coils has the best comprehensive heat transfer performance

under the condition with constant heat flow(240 Key Words： flat-plate solar collector

multiple spiral coils

field synergy

heat transfer enhancement Abstract: Keywords: Foundation: Authors: JIN Guang;WANG Zhengwen;TIAN Rui;YU Ye;