【作者】 李建华；

【导师】 郑加强；

【作者基本信息】 南京林业大学 ， 机械设计及理论， 2013， 博士

【摘要】 在能源日益紧张的今天，固态发酵技术因其发酵时间短、能耗低、得率高、环境污染小等优点而具有非常广泛的应用前景，现代固态发酵设备也要适应这种广泛性的需求。本文在分析国内外固态发酵设备应用与研究的基础上，针对既能实现物料灭菌、降温、原地接种，又能在线检测并控制物料温度、湿度、氧气含量等的多功能纯种固态发酵设备，设计了基于托盘平动机构运动无干涉及空间利用率最高的固态纯种发酵设备及其链传动系统。利用固-液两相流理论分析两相流体中微生物的受力，并推导了衡量流体微元体损伤的能量耗散率公式。通过仿真和试验验证，系统地研究了喷头类型、喷雾特性参数等因素对喷雾接种效果的影响。论文设计了一种新型的带有上下翻盖的托盘平动固态发酵机构，将接种管引入密封发酵罐内，在对罐内固态基质物料灭菌后，再通过通入罐内的喷雾接种系统的喷头均匀地将雾状菌种喷洒在固态物料表面，实现在同一发酵罐内完成物料的灭菌、冷却、原地接种和发酵，分析了固态发酵各工艺参数对发酵过程和产品得率的影响以及对各工艺参数的控制策略，通过发酵过程的自动控制，创造良好的生产条件，保证真正意义的纯种固态培养，以得到生长好且质量均匀的产品，同时又便于工业规模的放大。利用Matlab，对发酵罐内托盘的三种排布方式下的各种情况进行了基于托盘运动不干涉的各机构参数的初步求解和精确求解。对喷雾接种时生物颗粒流体系统的两相流进行了分析，讨论了由微生物和无菌水所组成的固-液两相流的流态特征，对喷雾接种两相流体中微生物的受力进行了分析。分析了用流体微元体能量耗散率定量衡量反映流体微元体对处于其控制中的微生物颗粒综合应力作用引起损伤的理论依据、可靠性及实用性，在微生物固态发酵与多相流体力学的交叉学科领域内具有突破性的理论意义。采用CFD计算流体动力学软件仿真和试验验证的方法对喷头类型、喷雾参数等因素对喷雾接种效果的影响进行了系统的研究。本文设计并制造了一套喷雾接种试验系统，确定了相应的测试方法。在FLUENT里创建了一个通过流场信息来计算能量耗散率的用户自定义函数，在合理设置边界条件和初始条件的基础上，对本文采用的三种类型的试验喷头在不同孔口尺寸、入口压力等的条件下的压力和能量耗散率等内部流场进行了数值模拟。试验和仿真结果表明：用喷雾接种实现纯种固态发酵过程的自动化、保证接种的均匀性是可行的，可以找到保证接种后微生物存活率的最佳喷雾特性参数；不同的喷头极限能量耗散率不同，并且出现极限值的位置也不同，在试验喷头和喷雾特性参数中，涡流扇形雾喷头TT1102在喷雾压力为0.3MPa时的能量耗散率最低、菌种死亡率最小。试验和仿真结果对利用喷头喷洒活性生物具有非常重要的参考意义。更多还原

【Abstract】 Solid state fermentation (SSF) technology has a very wide range of applicationson account of the increasingly energy shortage at present, especially on account ofshort fermentation time, low energy cost, high product yield rate and lessenvironmental pollution for SSF. Modern solid-state fermentation equipment shouldalso adapt to this extensive demand. Analyzing the applications and researches of thesolid-state fermentation bioreactor in home and abroad, a multifunctional solid-statefermentation bioreactor with keeping bacteria pure was proposed, which could notonly realize the sterilizing, cooling, inoculation and fermentation, but inspect andcontrol the temperature, humidity, oxygen contents of the materials. A solid-statefermentation bioreactor with pure bacteria and its chain transmission system weredesigned based on the movement of the translational tray mechanism withoutinterference and the space rate of the equipment with the highest utilization. Based onthe theory of fluid dynamics and particles dynamics, the microorganism particles’properties on its motion in the solid-liquid two-phase flow of the experimental nozzleswere analyzed. Energy dissipation rate to quantify the microbial particles’ damagewithin hydrodynamic stresses were analyzed. The numerical simulations of thenozzles were compared with experimental results to evaluate the effects of nozzletype, spraying parameters on the relative viability after flow through each nozzle type.A new type of solid-state fermentation bioreactor with a tray mechanism whichhas a kind of top and bottom turn-covers was designed.The inoculating tube wasarranged into the hermetic bioreactor. After sterilization, the nozzle of the inoculationspraying system can spray the bacterium on the solid substrate, to realize sterilizing,cooling, inoculation and fermentation in one solid-state fermentation bioreactor. Theeffect of process parameters on the fermentation process and the yield rate of productsand the control strategy were analyzed. By the automatic control of the fermentationprocess, it can create a good production conditions, ensure the pure solid-state fermentation indeed and the high quality of products. These also make it easy toenlarge to an industrial scale.Based on the Matlab, the mechanism parameters of the three arrangements withvarious situations were solved preliminarily and precisely based on the movement ofthe tray without interference and the space rate of the equipment with the highestutilization.The solid-liquid two-phase flow of the microorganism particles’ sprayinoculation fluid system was analyzed. Fluid characteristics of the two-phase flowcomposed of microorganisms and sterile water was discussed and the forced state ofthe microorganism particles was also analyzed. The energy component was deducedand discussed and the theoretical basis, reliability and practicability of the energydissipation rate which can quantify the microbial particles’ damage withincomprehensive hydrodynamic stresses were also discussed and analyzed.The effect of nozzle type, spraying parameters on the results of the sprayinginoculation was studied by simulation using FLUENT. A set of spraying inoculationexperimental flow device was designed and manufactured, at the same time, anappropriate test method was determined. A user-defined function was created inFLUENT to compute the energy dissipation rate from the flow field information. Bysetting reasonable boundary conditions and initial conditions, simulations of threetype nozzle’s flow field of the pressure and energy dissipation rate were conducted foreach size of nozzle and the experimental inlet pressure. Experimental and simulationresults showed that it was feasible to use spraying inoculation to realize automationand pure solid state fermentation process and ensure uniformity of the inoculation.The best spraying characteristic parameters can be found to ensure of microbialviability after inoculation. It also can be found that the maximum energy dissipationrate of different type nozzles were different, position where the maximum value atwas also different. Experimental and simulation results showed that the energydissipation rate of the Turbo TeeJet Flat-fan nozzle TT1102at the inlet pressure of0.3MPa was the lowest among the experimental nozzle type and size and the sprayingcharacteristic parameters. The results of experiment and numerical simulation will have certain reference value and directive significance to the biological spraying toavoid hydrodynamic damage to biological agents.更多还原