脉冲式烟雾水雾机工作频率影响因素研究

Influence Factors of Working Frequency of Pulsed Smoker/Fogger

脉冲式烟雾水雾机以脉冲发动机为动力,可施放烟雾或水雾,从而满足植物不同生长时期的施药要求。脉冲式烟雾水雾机工作频率取决于其声学结构条件、加热条件以及药液烟化或雾化时反馈作用共同耦合时的振荡频率。如不满足任一条件或反馈扰动过大,则无法形成振荡系统,或使原有的系统停止振荡,从而导致发动机熄火。通过改变脉冲发动机油门开度、药液类型(用0^#柴油和清水代替热雾剂农药和水雾剂农药)以及进入喷管内的药液流量,对脉冲式烟雾水雾机进行了工作频率的影响因素研究。结果表明,不喷药状态时,实际工作频率高于理论工作频率,平均相对误差为26.6%;喷药状态时,热雾剂或水雾剂农药进入喷管内热力烟化或雾化后,均会引起实际工作频率的下降,水雾剂农药雾化后工作频率的下降幅度大于热雾剂烟化后的频率下降幅度,水雾剂农药热力雾化比热雾剂热力烟化对原有脉动燃烧振荡系统的扰动大。据此重新构建了脉冲式烟雾水雾机喷烟雾或喷水雾工作频率的数学模型。喷烟雾和喷水雾状态下,工作频率与药液流量之间均呈负比例线性关系,其比例系数分别为-0.1357、-0.1157 Hz·h/L;工作频率与燃油消耗率之间均呈正比例线性关系,其比例系数分别为38.58、30.73 Hz·h/L。应用新构建的模型所引起的最大相对误差只有2.2%和1.4%,表明构建的工作频率数学模型可用于脉冲式烟雾水雾机在常规喷药量范围内工作频率的计算。

The pulsed smoker/fogger powered by pulse engine could meet different requirements on disease and pest control for application smoke or fog during the different growth periods of plants.The working frequency of pulsed smoker/fogger is depending on the pulse frequency when the acoustic structure condition,heating condition,and feedback effect of pesticide were coupled together.Once any condition was not satisfied or the feedback disturbance was too large,an oscillating system could not be formed or the original oscillation system would stop to the pulse engine flameout.The experiments of working frequency were performed,the data were processed and analyzed by changing the throttle opening of pulse engine,replacing hot smoke pesticide by 0#diesel,replacing water fog pesticide by clear water,and changing the liquid flux entering into the exhaust pipe.By using the acoustic resonance frequency equation,it was found that the actual operating frequency was higher than the theoretical value without spraying,and the average relative error was 26.6%.In the state of spraying,when the hot smoke or water fog pesticide was injected into the exhaust pipe,the original working frequency would be decreased after the heat fuming or atomization.However,the reduction of the working frequency of water fog after atomizing was much larger than that of the hot smoke after fuming.In other words,the water fog pesticide after atomizing had more disturbances to the original pulsating combustion oscillating system than the hot smoke after fuming.The calculation formula of working frequency of the pulsed smoker/fogger under spraying smoke or water fog were established.The actual working frequency was negatively proportional to the liquid flux.The linear ratios were-0.1357 Hz·h/L and-0.1157 Hz·h/L,respectively.The actual working frequency was proportional to the fuel consumption rate.The linear ratios were 38.58 Hz·h/L and 30.73 Hz·h/L respectively.The maximum relative average errors caused by these two equations were only 2.2%and 1.4%respectively.This demonstrated that within the range of the conventional spraying amount,it was feasible to calculate the corresponding working frequency by the established equations.