Testing of Promising Technical Solutions in the Design of a Prototype Initial Standard for the Measurement Unit of Volumetric Wastewater Flow Rate

In the Russian Federation, work is underway to create a national of the highest accuracy for the unit of volumetric wastewater flow rate. The development of this standard is based on measurement practices for wastewater quantity in both pressurized pipelines and non-pressurized pipelines (open channels). Significant experience has been accumulated in measuring water flow in pressurized pipelines, and a system for the metrological support of measuring instruments has been established. However, measuring water flow in non-pressurized pipelines remains a challenging metrological task due to the hydrodynamic specifics of forming a non-pressurized, non-turbulent water flow and the shortcomings of the existing metrological support system.The authors of the article examined the results of the first stage in creating the highest-accuracy standard for the unit of volumetric wastewater flow rate – the creation of a model of a prototype initial standard. The development of the prototype began with an analysis of publications (from sources including Rospatent, Espacenet, Scopus, eLIBRARY.RU, and the Federal State Information System of Rosstandart, etc.) on the specified topic. Based on this review, technical and technological solutions were selected for implementation in the prototype’s main systems and were subsequently tested. For example, the study presents approaches that enable the formation of a fully developed non-turbulent flow in an open channel (flume) with a nearly two-dimensional velocity profile in its cross-section. These approaches are designed to ensure the required metrological characteristics across a volumetric flow range Q V from 1 to 100 m³/h.The proven promising technical solutions in the prototype standard’s main systems have enabled the following: implementation of non-turbulent flow in an open channel (flume); achievement of the specified metrological characteristics within the declared range of volumetric flow rate Q V from 1 to 100 m³/h; maintenance of the water temperature in the storage tank and the water circuit within the specified temperature range from 15 to 25 °C; development of engineering recommendations for determining heat influxes to the water in the prototype’s circuit. These recommendations form the basis for defining the capacity requirements of the water cooling system, which is to be based on commercially available refrigeration units (chillers). The results of the experimental research presented in the article will pave the way for the design and development of an initial standard for the unit of volumetric wastewater flow.The establishment of a national of the highest accuracy for the unit of volumetric wastewater flow rate will strengthen the metrological sovereignty and international standing of the Russian Federation.