The main objective of this work is a comparison of measurement techniques that have been modified allowing for rheological measurements of agricultural digestate without a required pretreatment. This includes detailed information on the theoretical physical background, experimental set-up and for mixing rheometers also the calibration procedures, namely the Metzner-Otto concept/Rieger-Novak method and the Couette analogy. Furthermore, the advantages and disadvantages of rotational rheometers, torsion viscometers, mixing rheometers, pipe viscometers and the so-called ball measuring system are stated. As a result, pipe viscometers are found to be applicable for field experiments, while mixing rheometers were found to be the most suitable choice for lab-scale experiments. Within this work, a recommendation for a possible configuration for a mixing rheometer is provided.

Moreover, this article gives an overview of research works dealing with the rheological behavior of digestate from agricultural biogas plants and first identified influencing factors. Investigated samples in the featured research works all exhibit a non-Newtonian shear-thinning flow behavior and the power-law model was applied the most. The most common identified influencing factors include temperature, total solid content, feedstock, particle size and anaerobic digestion, amongst others. However, observed correlations between these factors and the flow behavior and viscosity, respectively, to date are rather qualitative then quantitative, and extensive, systematic studies have yet to be carried out in order to establish quantitative relationships in between influencing factors. Based on the survey of relevant literature, recommendations for the measurement procedure and documentation of rheological measurements of digestate are provided.

这项工作的主要目的是比较测量技术，这些测量技术经过修改，无需进行预处理即可进行农业消化液的流变学测量。这包括有关理论物理背景，实验设置以及混合流变仪以及校准程序的详细信息，即Metzner-Otto概念/ Rieger-Novak方法和Couette类比。此外，还陈述了旋转流变仪，扭转粘度计，混合流变仪，管道粘度计和所谓的球测量系统的优缺点。结果，发现管道粘度计可用于现场实验，而混合流变仪被认为是实验室规模实验的最合适选择。在这项工作中，

此外，本文概述了处理农业沼气厂消化液流变行为的研究工作，并首先确定了影响因素。特色研究工作中的调查样品均表现出非牛顿剪切稀化流动特性，并且幂律模型得到了最广泛的应用。最常见的影响因素包括温度，总固体含量，原料，粒度和厌氧消化等。然而，迄今为止，这些因素与流动特性和粘度之间的相关性迄今仍是定性的，然后是定量的，为了建立影响因素之间的定量关系，尚未进行广泛的系统研究。根据相关文献的调查，