The complex structure of double inlet gas flue has a significant influence on gas flow field distribution in a 1000MW coal-fired boiler’s low temperature economizer. In order to optimize gas flow field of the low temperature economizer with double inlet gas flues and reduce its failure rate, this paper presents a flow field simulation of the low temperature economizer based on the computational fluid dynamics (CFD). This numerical simulation was operated by using porous media model instead of the complex structure inside heat exchanger and the standard k-epsilon model. Velocity contours of a same vertical cross-section inside of inlet gas flue of the heat exchange zone in different numerical simulations were evaluated by the evaluation standard of RSM. The results of numerical simulation show that the main reasons for uneven distribution of flow field in economizer and its inlet gas flues are unequal diameter of flue elbow and straight flue, unreasonable setting of guide plate and diffusion flue elbow. After making structural optimization of the low temperature economizer such as equalizing elbow to the straight flue diameter and setting the guide plate reasonably, the flow field in the low temperature economizer and its flues are obviously improved.
The numerical simulation calculation of air-assisted atomizer internal gas flow field is done, the distribution and changes of the nozzle inside flow field total pressure, velocity, and dynamic and static pressure are analyzed. The analysis shows that the total pressure loss is less; due to the effect of gas viscous, the high-speed air flow is formed vortex flow near the outlet nozzle and the mutual influence between the dynamic and static pressure. A new way is supported for optimizing the nozzle structure according to these studies.
The section mutation of a pipe affects the interior flow field seriously. Numerical simulation of the two-dimensional steady gas flow field of two types of section mutation pipe was processed. By comparing it with equivalent section pipe’s interior flow field, the effects of section mutation of pipe on pressure distributing and velocity distributing were analyzed. The results are commendably consistent with the theories of one-dimensional adiabatic frictional pipe flow. Ensuring the section of the compressed gas pipe to be coherent and using the bell and spigot joint if necessary are presented.
Numerical Simulation of the Gas Flow Field in the Cold Storage and Freezing Process of Procambarus Clarkii