Research Of Gas-liquid Heat Pipe Exchanger Used In Recovery Of Flue Gas Heat At Low Temperature

Smoke gas waste heat is a kind of high quality renewable energy sources, and it has become an important object of energy saving and emission reduction. Due to low Grade, scattered distribution, dew point corrosion,conventional heat exchanger can't meet its demand. Because of high heat transfer efficiency, compact structure, convenient maintenance, heat pipe exchanger is very suitable for recovery of waste heat in lowtemperature smoke gas. This paper will apply heat pipe exchanger to recovery of waste heat in low-temperature smoke gas, and explore the feasibility and method of enhancing performance.Firstly, this paper analyzes the convection features of gravity heat pipe and heat pipe heat exchanger at the aspect of theory, and design based on actual project requirements:(1) it clarifies the heat transfer mechanism and the heat resistance property of gravity heat pipe;(2) it analyzes the influence of heat pipe shell design, rib efficiency, length than, tube drainage mode for the heat transfer performance of heat pipe heat exchanger;(3) based on related project,it makes theory analysis and designs a heat pipe heat exchanger for recovery of waste heat;(4) it puts forward the optimization scheme for theory design at the aspect of tube spacing, based on the characteristics of heat pipe.Then, this paper uses CFD to build the simplified model of heat pipe heat exchanger,and run numerical simulation for tube spacing and water flow:(1) it explores the law of the heat transfer and resistance under different tube spacing;(2) it explores the law of the heat transfer and resistance under different water flow. The results indicate that:Heat transfer performance and resistance is remarkably influenced by tube spacing and water flow ——reducing tube spacing is beneficial for the improvement of heat exchanging,so tube spacing should be small during the design of heat pipe exchanger;increasing water flow is beneficial too, but it should be controlled within a certain range, otherwise it would lead to much resistance loss and the reduce of comprehensive technical and economic performance.Lastly, the paper conducts a test based on practical project. The test results matches the numerical simulation results well. It verifies the reliability of the numerical simulation method and the feasibility of using heat pipe exchanger in projects of recycling waste heat from low-temperature smoke gas.In conclusion, this paper uses theoretical analysis computation, numerical simulation and test for the qualitative and quantitative research of heat pipe exchanger. The related numerical simulation method and research result has positive effects on recycling waste heat from low-temperature smoke gas.