| With the rapid development of the data center and computer technology,the improvement of server performance brings not only a significant increase in heat flux density,but also a great test for the heat dissipation capacity of data centers.In order to ensure the safe and stable operation of the equipment in property temperature range,the data center mainly adopts the air-conditioning system.In the air conditioning system energy saving way,using the natural cold source refrigeration for indirect which can better satisfy the data center strict requirements of humidity and cleanliness is be more respected.In order to avoid the problems in data center such as water leakage,this paper uses R134a-the separated type heat pipe which using natural cold source refrigeration indirectly,within the data center temperature range to study the factors affecting the heat transfer performance of R134a-the separated type heat pipe.Firstly,experiments on the start-up performance of R 134a-separate heat pipe were carried out.The influences of heating power methods and start filling rate were analyzed.It was found that there was a lowest limit of filling liquid rate which was 70%in this system and there was a minimum starting power.In this experiment studying,when filling rate was 90%,the minimum starting power was 30W.when the R134a-SHP at higher filling rate,it would take longer time to start-up.Secondly,on the performance of the separated type heat pipe research,we focuse on heat pipe cooling effect and circulation ratio of the system,becouse they reflect the capability of thermal diffusion between heat source and heat exchanger and heat transfer capability through air convection.In this paper,we study variation of the circulation ratio of R134a-SHP in different heating power,different wind speed and different rising tube diameter.Experiments found that at small heating power range,the separated type heat pipe evaporator dryness will be influenced,and it will decrease with the increase of heating power,and this phenomenon will gradually disappear along with the increase diameter of rising tube. |
