变频调风时通风系统风量可靠性评价数学模型

以合格的风量范围为视角对风机变频调风时通风系统风量的可靠性进行理论研究，基于大数定律，充分考虑风量波动性的同时，可将概率向频数比率转化，以此对变频调风的分支风量可靠度进行定义。推导了对自然风压考虑与否的两种常态频率风量与所需频率风量的转换公式，基于此，通过测量常态频率的风量，预测所需频率风量的可靠度，进而在风机调频前对未知可靠度进行预判。以分支数为行、测量次数为列，推导并构建通风系统的风量可靠度矩阵和可靠值矩阵，前者强调超限次数，后者强调超限额，从理论上分析了其与风机频率的关系，并基于转换公式预测所需频率可靠度/值矩阵。

Mathematical model of reliability evaluation on air volume of ventilation system in volume adjustment by frequency conversion

The reliability on air volume of ventilation system in volume adjustment by frequency conversion of fan was theoretically studied from the perspective of qualified air volume range. Based on the law of large numbers, the probability could be transformed to frequency ratio with fully considering the fluctuation of air volume, so the reliability of branch air volume in volume adjustment by frequency conversion could be defined. Two conversion formulas for transforming the air volume under normal working frequency into the air volume under the required frequency with or without considering the natural ventilation pressure were deduced. On this basis, the reliability of air volume under the required frequency can be predicted through measuring the air volume under normal working frequency, then the unknown reliability can be predicted before volume adjustment by frequency conversion of fan. Taking the branch number as the row and the measuring times as the column, the reliability matrix and reliability value matrix on air volume of ventilation system were deduced and constructed, in which the former emphasizes the overrun count and the latter emphasizes the overrun value. The relationship between the matrices with fan frequency was theoretically analyzed, as well as the forecast on reliability matrix and reliability value matrix of the required frequency based on the conversion formulas.