Factors affecting the heat transfer effect of heat exchange tubes

Speaking of the heat exchange tube, it is one of the components of the heat exchanger, and everyone should be familiar with it. If there is no heat exchange tube, the heat exchange process of the heat exchanger cannot be carried out. Therefore, the choice of heat exchange tubes (such as seamless carbon steel heat exchanger tubes) will directly affect the heat exchange efficiency and heat exchange effect of the heat exchanger. So, what aspects of the heat exchange tube will affect the heat exchange effect?

1.The material of the heat exchange tube

 Carbon steel, low-alloy steel, stainless steel, copper, copper-nickel alloy, aluminum alloy, titanium, etc. are commonly used heat exchange tube materials; graphite, ceramic, and PTFE are non-metallic materials. Since most of the medium to be transmitted in the heat exchanger is hot water or corrosive liquid, if you choose a copper tube heat exchange tube, the oxide layer of the copper tube will increase with the use of time, the thicker the internal The more dirt, the worse the heat transfer effect. Even if it oxidizes slowly, stainless steel will not oxidize. In addition, according to the law of thermal conductivity and thermal resistance, thermal conductivity will not change, and the smaller the thickness of the wall of the tube, the smaller the thermal resistance and the greater the heat transfer coefficient. Due to strength and wear, the wall thickness of copper tubes cannot be less than 1.2mm, and the wall thickness of stainless steel tubes can be as thin as about 0.5-0.8mm, so now people mostly choose stainless steel tubes as heat exchange tubes.

2.The thickness and shape of the inner wall of the heat exchange tube

 Stainless steel corrugated tubes are commonly used heat exchange tubes in heat exchange equipment. Enhanced heat transfer can be achieved through its unique ultra-thin-walled corrugated tube. The height difference between the wave crest and the wave trough causes the fluid to be strongly disturbed. Even if the flow velocity of the fluid is very low, it can be in a turbulent state; at the same time, the temperature gradient of the thin tube wall is small, which greatly reduces the thermal resistance of the tube wall and improves the tube wall. The heat transfer coefficient inside and outside, so that the total heat transfer coefficient increases.

3.the surface smoothness of the heat exchange tube

 Compared with the heat exchange tube, when the threaded tube is used as the heat exchange tube, in the formal heat exchange process, the medium flowing in the threaded tube will rotate along the threaded tube around its radius of curvature, resulting in the tube being radial And circular. The secondary reflux along the flow direction makes the convective heat transfer coefficient larger, so the heat transfer effect of the threaded tube is better. Therefore, most of the heat exchange tubes in the industrial production we see every day are stainless steel threaded tubes.

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