The main part of the project was related to the detection of water leakage from the district heating (DH) system and to the heat loss in wet insulation. Measurements of water leakage from the (DH) network have been carried out by use of the ‘‘closure areas’’ method. The method reliability was in the range of 4 m3/h. Leak detection was also tested by thermography. IR camera can be a reliable leakage indicator if temperature change at selected pipeline location is registered periodically. Heat losses caused by the insulation wetting were estimated to be 4% of the heat input. The experimental analysis of heat loss in wet insulation for the pipeline in channel and for the pre-insulated pipeline was performed. Heat loss was within 200 W/m and 380 W/m. The thermal conductivity of wet insulation was about 1 W/(mK). A numerical simulation for the real system and wet insulation showed that heat loss increases by 2.2 times on the pipeline in channel and by 3.9 times on the pre-insulated pipeline.
F.10 Improvements to an existing technological process or technology
COBISS.SI-ID: 13281307The paper presents experimental work in a Wurster type coater. The pressure drop in the draft tube during the coating process was measured. The purpose of this study was to investigate the potential use of pressure drop fluctuation analysis to estimate quality parameters such as coating thickness uniformity, coating yield and degree of agglomeration. Combining different Wurster chamber geometries, intake airflow rates and draft tube heights, 20 coating experiments were performed. Based on Fast Fourier Transform analysis of raw pressure drop signals, four flow regimes were identified. The characteristic frequency bands were: 2-5 Hz (regime A), 13-16 Hz (regime B), periodicity of low frequencies (regime C) and exhibiting of two characteristic bands, 2-5 Hz and 13-16 Hz (regime D). In a particular coating experiment, the relative standard deviation (RSD) of the pressure drop signal and the identified flow regime provided sufficient information for a reliable estimate of coating quality parameters. Pressure drop fluctuations did not change significantly during the coating process, which provides an acceptable assessment of the aforementioned parameters even at the beginning of coating.
F.08 Development and manufacture of a prototype
COBISS.SI-ID: 3453553Acoustic resonance in liquid-filled pipe systems is a nundesirable phenomenon that cannot always be prevented. It causes noise, vibration, fatigue, instability, and it may lead to damage of hydraulic machinery and pipe supports. If possible, resonance should be anticipated in the design process and be part of the hydraulic-transients analysis. This paper describes acoustic resonance tests carried out at Deltares, Delft, The Netherlands, within the framework of the European Hydralab III programme. The test system is a 49 m long pipeline of 206 mm diameter that is discharging water from a 24 m high reservoir through a 240 mm2 orifice to the open atmosphere. The outflow is partly interrupted by arotating disc which generates flow disturbances at a fixed frequency in the range 1.5 Hz to 100 Hz. In previous studies [1,2] a similar system was analysed the oretically. Here in experimental data are presented and interpreted. Steady oscillatory behaviour is inferred from pressures measured at four different positions along the pipeline. Heavy pipe vibration during resonance was observed (visually and audibly) and recorded by a displacement transducer.
F.18 Transfer of new know-how to direct users (seminars, fora, conferences)
COBISS.SI-ID: 13182235