Development of a non-invasive thermometric system for fluids in pipes
In this paper a non-invasive thermometric system for the measurement of the temperature of fluids in pipes based on the dual heat flux method is presented. The proposed solution is a possible alternative to the employment of thermowells in industrial applications. The proposed sensing system, is based on the dual heat flux method, a technique used in biomedical field. The applicability of such a measurement system in the field of interest is studied taking into account its component performance and how they influence the overall system behavior. A prototype system exploiting RTD sensors with measurement accuracy lower than 1°C has been designed, obtaining performances comparable to the thermowell ones. To reach such an accuracy a dedicated front-end electronics has been developed.
An evaluation of thermowell’s integrity in RCP test facility
Abstract An RCP test facility has been constructed at KAERI. During the commissioning startup operation, one of thermowells was cracked due to the high-speed coolant velocity. To complete the startup operation, a modified design of the thermowells was proposed, and all the original thermowells were replaced by the modified ones. From an evaluation of the original and modified designs of the thermowells according to the recent PTC code, the original design did not satisfy the new or old requirements, and the modified design simply satisfied the old requirement. The cracked surface of the original one was owing to the fatigue stresses in transverse oscillations. Two of three modified thermowells were found to be bent after about a 4.1 × 10 8 fatigue cycle operation. Their tapered-shanks came in contact with the nozzle walls and each showed a rim of deformation on the root. The modified ones suffered the fatigue stresses in in-line oscillations and became bent in in-line direction. A new design of thermowells with a straight shape and shorter unsupported length satisfying the current PTC code requirement was developed and installed in the RCP test facility. For the new design, additional modal analysis based on the finite element method was performed to check the dynamic behaviors using the ANSYS code and it was found that the PTC code predicted more conservative frequencies for the evaluation of dynamic behaviors in thermowell design.
The incidence of dead and dying fish in the Moray Firth, September 1963
Dead and dying fish were reported from the Moray Firth during a period of 15 days in September 1963. The initial mortalities were in the inner Firth, but they later spread outwards, especially eastwards along the southern shores of the Firth. Mass mortalities of the lugworm (Arenicola marina) also occurred in Scottish waters in 1962 and 1963, and at Balintorein Easter Ross fish and lugworm mortalities were contemporary.