Simulation And Optimization On The Spraying And Inoculating Nozzles Of Solid-state Fermentation Based On The Survival Rate Of Bacteria

Nowadays with the growing energy shortages and environmental problems, also with the enhancing consciousness of environmental protection, new energy resources, new methods and new technologies have been aroused more and more attention. Biological engineering technology, as a new clean technology, is developing continuously and promoting the sustainable development of human economy since the 21 th century. As the basis of biological engineering technology, microbial solid fermentation technology has produced various products and has become one of the main technologies to deal with the waste of agriculture and forestry. In the system of pure solid-state fermentation, some previous researches showed that conventional nozzle will damage the microbial of fermentation. So it is very important to design a microbial nozzle for solid-state fermentation technology. Consequently, this paper mainly analyzed the inner structures and related parameters of nozzles which related to the microbial particles’ damage based on the general spraying nozzles, in order to find a microbial nozzle for solid-state fermentation system to promote the technology of solid-state fermentation and biological pesticide.The advantages and disadvantages among the various methods which quantifying the microbial particles’ damage within hydrodynamic stresses were compared and analyzed according to the existing research methods in this paper. It also analyzed the complex stress of solid particles in the flow field. The viscous energy dissipation rate was chosen as the final evaluation of microbial activity during the process of nozzle’s spraying through theoretical analysis and practical application.Flat fan nozzles and hollow cone nozzles which were frequently used were calculated and designed by using the nozzle’s theories. Three models of each nozzle with different internal structures were also established in Catia in this paper according to existing equipment of solid-state fermentation.The internal flow fields of each nozzle model were simulated by using Ansys Fluent, a popular software of fluid analysis. And based on the secondary development of Ansys Fluent, it also researched on the influence of the inner flow fields on the energy dissipation rate and its distribution. A more suitable internal structure was chosen at last to contain the microbial activity from the two types of nozzles.For the two types of nozzles which were chosen, the paper optimized and designed the main structure parameters of the flat fan nozzles and hollow cone nozzles based on the simulation of internal flow fields, especially the extreme value and distribution of energy dissipation rate. At last, this paper found some suitable structure parameters of internal structure for the microbial spraying and inoculating.The models were finally produced by using rapid prototyping technology. Testing experiments were conducted to compare the results of simulation. The results of experiment and simulation showed that both the inside structure and key parameters of nozzles effected on the microbial activity during spraying and inoculating and it was a feasible way by optimizing the cavities and the key structure parameters of nozzles to improve the microbial activity when spraying.