The Research On Heat Transfer And Friction Characteristics Of The Grdding Ribbed Channel

An experimental investigation on the flow and heat transfer characteristics in rectangular channel with internal netted rib turbulators is conducted.The experimental model is a rectangular section of 15.2×187mm~2, which is composed of two aluminum plates. The angles between the internal netted rib turbulators and the flow direction are 45?for the one plate and 60?for the other , or both 45?for two plates. In the experiment, the Re numbers changes from 0.4×10~4～1.5×10~5, rib width-to-pitch are 0.25, 0.3 and 0.5, rib width-to-height are 0.25, 0.3 and 0.5, the rib height-to-hydraulic diameter ratio is 0.246.The experimental results show that the gridding rib has significant effects on heat transfer enhancement. The Nuselts number increases as Re increases. The channel of t/p=0.5 shows the best heat transfer characteristics, and t/e=0.3 gives the the best heat transfer characteristics. Especially, the 45°/45°channel could obtain more obvious heat transfer enhancement than 45?60?channel.The gridding rib causes a large enhancement in flow friction. The channel of t/e=0.3 causes the largest friction in 45°/45°channel. In different t/p values, t / p=0.5 gives the largest friction in both 45°/45°and 45°/60°channels.The value of the criterion is used to consider the comprehensive efficiency. The value for present study range from 0.2 to 0.4. Comparing the 45?45?and 45?60?channel, we find that the comprehensive efficiency of the former is significantly superior to the latter. In chosen t/e values, t/e=0.3 and 0.5 has the better effect in 45?45?channel, and in 45°/60°channel t/p =0.3 and 0.5 are the better in low Re number.and t/p =0.25 is the better one in high Re number.large amount of experimental data is obtained in the present study on flow and heat transfer inside a gridding rib turbulator cooling channel, which could be helpful for the design of a new type turbine cooling channel.4545?channel, t/p=0.5 for 45?60?channel seem better than other cases.A large amount of experimental data is obtained in the present study on flow and heat transfer inside a gridding rib turbulator cooling channel, which could be helpful for the design of a new type turbine cooling channel.