Study on Heat Transfer Performance and Parameter Improvement of Gravity-Assisted Heat Pipe Heat Transfer Unit for Waste Heat Recovery from Mine Return Air

One of the effective methods for energy conservation and emission reduction in coal mines is to utilize waste heat recovery technology recover mine return air heat. The gravity pipe widely used due its sustainable economic advantages, but transfer a complex process influenced by multiple parameters. A single-tube resistance model calculation based on enthalpy difference were established exchange tubes. Four typical application cases low flow rate number tube rows selected, their characteristics tested onsite analyzed. It was found that there problems such as overall efficiency, fresh outlet temperature, risk icing final section. effects parameters performance studied, outer diameter, spacing, finned diameter. air-resistant force exchanger increased with increase spacing decrease coefficient first then decreased configuration improvement scheme high proposed here. Taking Case 2 an example, temperature distribution before after compared results show system significantly improved. Without increasing tube, reduced 1.1 °C, 4.1 °C lower than improvement, further recovering air. condensate water film greater 0.5 avoiding problem section, reached 5.2 7.8 efficiency from 56.7% 66%.