Annotation: The effective documents in the field of metrological support require evaluating measurement uncertainty during measuring instrumentation calibration. In Ukraine, there is no regulated procedure of uncertainty calculation during measuring instrumentation calibration, which causes the necessity of developing such procedure. This article proposes the measurement uncertainty calculation procedure during measuring instrumentation calibration, according to which the following calculations shall be made: a) of standard uncertainty of A type for corrected observation results obtained during calibration; b) of standard uncertainties of B type caused by error or uncertainty of working standard applied, calculation discreteness or calibrated measuring instrument division value, variation of calibrated measuring instrument indications; c) of total standard measurement uncertainty; d) of augmented measurement uncertainty. As an example, the results of calculation of augmented measurement uncertainty during calibration are presented: – for 795M107B vibrometer in complete set with AC102-1A accelerometer; – for alternating voltage measurement channel of a measuring and computing complex of MIC type; – for a manometer of MT type. The obtained results of measurement uncertainty calculation are presented in the form of tables of measurement uncertainty budget, which shall be entered in the measuring instrument calibration certificate together with the observation results obtained during calibration. The proposed uncertainty calculation procedure is applicable for the given types of measuring instruments whose calibration is performed by method of direct measurement of known measurement values represented or controlled by working standards.

Annotation: At Yuzhnoye State Design Office, the Cyclone-4 launch vehicle 3rd stage engine has been developed and is under testing. For adjustment of the engine and test bench systems, in the first firing tests the radiation-cooled nozzle extension was replaced with a steel water-cooled one. It was planned to start the engine with water-cooled nozzle extension without vacuumizing and without gad dynamic pipe, which conditioned operation with flow separation at the output edge of water-cooled nozzle extension. Therefore, the calculation of flow in the nozzle with water-cooled extension, flow separation place, and thermal load on watercooled nozzle extension during operation in ground conditions is an important task. Selection of turbulent flow model has a noticeable impact on prediction of flow characteristics. The gas dynamic analysis of the nozzle with water-cooled extension showed the importance of using the turbulent flow model k-ω SST for the flows with internal separation of boundary layer and with flow separation at nozzle section. The use the flow model k-ω SST for calculation of nozzle with flow separation or with internal transitional layer allows adequately describing the flow pattern, though, as the comparison with experimental data showed, this model predicts later flow separation from the wall than that obtained in the tests. The calculation allows obtaining a temperature profile of the wall and providing the recommendations for selection of pressure measurement place in the nozzle extension for the purpose of reducing sensors indication error. With consideration for the special nature of the nozzle extension wall temperature field, the cooling mode was selected. The tests of RD861K engine nozzle with water-cooled extension allow speaking about its successful use as a required element for testing engine start and operation in ground conditions without additional test bench equipment.