On the use of high-throughput tube heat exchangers

I’m hoping experts can help; I’ll wait

“The term “high-throughput tube heat exchanger” is not accurate. Generally speaking, a higher processing volume means a higher throughput, and there is no specific limit for this value. So this question is meaningless.

High-throughput tube heat exchangers are efficient heat exchangers used to enhance boiling heat transfer. Its main feature is the creation of a metal porous layer on the outer or inner surface of the metal light tube, which enables efficient heat transfer at low temperature differences. This facilitates the hierarchical utilization of energy, improves energy efficiency, and reduces waste heat emissions. It can be widely applied in industries such as petroleum, chemicals, metallurgy, power generation, waste heat recovery, desalination, geothermal energy, and ocean thermal energy conversion. 1. Characteristics of high-throughput tube heat exchangers: 1) High-throughput tube heat exchangers have a high heat transfer coefficient. Since the boiling always remains in the nucleate boiling regime, the heat transfer coefficient due to boiling is 3 to 8 times that of a smooth tube, thereby significantly increasing the overall heat transfer coefficient of the boiling equipment. 2) The heat transfer temperature difference of high-throughput tube heat exchangers is small. Since the liquid transfers heat and vaporizes in the form of a thin film, under the same heat load the heat transfer temperature difference is only 1/4 to 1/7 of that of ordinary surfaces; boiling can begin at a heat transfer temperature difference of 0.6–1.0°C. It can also be applied to materials in biological and pharmaceutical engineering that are not suitable for boiling at high temperatures. 3) The critical heat load of high-throughput tube heat exchangers is high. The critical heat load of porous surface tubes is 1.5 to 2.0 times higher than that of plain tubes. 4) The high-throughput tube heat exchanger has strong anti-scaling capabilities. Since it is a porous-surface tube, the fluid circulation rate on the porous surface is 10 to 15 times that of a plain tube. The extensive liquid circulation cleans the surface of the heat exchange tubes, thereby granting them better anti-fouling properties than plain tubes, and they are less prone to coking. 5) The high-throughput tube heat exchanger offers a high performance-to-price ratio. By improving heat transfer efficiency and reducing the size of the equipment, it lowers the investment required for such equipment as well as the associated construction costs, thus offering a high cost-performance ratio. The suitable application areas for the high-throughput tube heat exchanger can be inferred from its structural characteristics and the principles behind heat transfer enhancement. 6) Enhanced boiling: The rate of heat transfer by boiling is closely related to the speed at which bubbles form on the heat transfer surface; in ordinary smooth tube heat exchangers, the vaporization nuclei that lead to bubble formation are located at the existing surface defects. A high-throughput tube features a porous metal thin coating applied to the surface of a regular heat exchange tube; this coating contains numerous micropores and interconnected tunnels, creating numerous artificial vaporization cores that greatly accelerate the rate of bubble nucleation. The interconnected porous layers, as bubbles grow and escape, accelerate the mixing of the local liquid due to siphonage effect, thereby enabling overall convective heat transfer. At the same time, the porous surface layer increases the heat transfer area, which is another important reason why high-flow tubes can enhance boiling heat transfer. In the process of boiling heat transfer, the superheating of the liquid is one of the necessary conditions for phase change. The surface roughness of ordinary light-tube heat exchange tubes is relatively low, and the radius of curvature of bubbles is also small; therefore, bubbles can be formed only at a higher superheat. High-flux tubes can reduce the superheat required for boiling, enabling intense nucleate boiling at a very low wall superheat; the wall superheat needed for boiling is only 1/7 to 1/8 of that in conventional tubes. Replacing traditional heat exchangers with high-flux tube heat exchangers is not only technically feasible but also results in a significant improvement in heat transfer efficiency. In cases where the heat source is a condensing medium, the overall heat transfer coefficient of high-flux tube heat exchangers of the same specifications is 2 to 5 times higher than that of plain tube heat exchangers. 7) Enhanced condensation: By utilizing the Gregorig effect, film condensation is induced at the tips of the serrations formed on the surface of the heat exchange tubes; the grooves at the bottom facilitate the rapid removal of this liquid film, reducing its thermal resistance and thereby achieving enhanced condensation. The longitudinal serrations, which increase the heat exchange area, are another important reason why porous high-flow surface tubes can enhance condensation.