scholarly journals Numerical simulation of a passive scalar transport from thermal power plants

Author(s):  
Alibek Issakhov ◽  
Aiymzhan Baitureyeva
2008 ◽  
Vol 598 ◽  
pp. 335-360 ◽  
Author(s):  
SUMAN MUPPIDI ◽  
KRISHNAN MAHESH

Direct numerical simulation is used to study passive scalar transport and mixing in a round turbulent jet, in a laminar crossflow. The ratio of the jet velocity to that of the crossflow is 5.7, the Schmidt number of the scalar is 1.49, and the jet-exit Reynolds number is 5000. The scalar field is used to compute entrainment of the crossflow fluid by the jet. It is shown that the bulk of this entrainment occurs on the downstream side of the jet. Also, the transverse jet entrains more fluid than a regular jet even when the jet has not yet bent into the crossflow. The transverse jet's enhanced entrainment is explained in terms of the pressure field around the jet. The acceleration imposed by the crossflow deforms the jet cross-section on the downstream side, which sets up a pressure gradient that drives downstream crossflow fluid toward the jet. The simulation results are used to comment on the applicability of the gradient–diffusion hypothesis to compute passive scalar mixing in this flow field. Computed values of the eddy diffusivity show significant scatter, and a pronounced anisotropy. The near field also exhibits counter gradient diffusion.


2018 ◽  
Vol 10 (10) ◽  
pp. 168781401879954 ◽  
Author(s):  
Alibek Issakhov ◽  
Aiymzhan R Baitureyeva

The number of thermal power plants is growing due to the industry development and the growth of energy consumption. This leads to an increase in harmful emissions in the atmosphere. There is a necessity to control the emission concentration level in the areas of power plants location. The aim of this work was to study the level of pollution concentration at different distances from the source. The mathematical model and the numerical algorithm were verified by solving test problems and comparing them with the experimental data and numerical results of other authors. Furthermore, the pollution distribution in three-dimensional case was investigated in a real physical scale. CO2 was considered as polluting gas. As a real example, the Ekibastuz SDPP-1 coal-fired thermal power plant was simulated. The remarkable feature of this thermal power plant is that the pollution emits from two chimneys of different heights (330 and 300 m). The results showed that due to the difference between chimney heights (30 m), the pollution concentration from the higher chimney dropped far away from source, than from the lower one (2160 and 1970 m, respectively). Obviously, building higher chimneys helps to reduce the harmful impact of emissions on the environment. Also, it can be used to control the emissions level at already existing power plants.


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