Analysis of thermal and mechanical stresses in the ceramic seal of the 1-MW(th) bench-model solar receiver. Final report
A study was undertaken to assess both analytically and experimentally the thermal/mechanical stress levels associated with the hot tube to manifold ceramic joint for the 1-Mw/sub t/ bench model solar receiver (BMSR) and to define appropriate design and/or material changes for this joint to provide an acceptably low probability of failure. To this end, thermal shock/thermal gradient and combined thermal/mechanical loading tests were designed, analytically modeled, experimentally carried out, and subsequently analyzed. Analysis of the current BMSR ceramic joint design and materials revealed that a rather low probability of success would be expected. From the experiments performed it was deduced that the current disc material has an apparent Weibull modulus of three to five for the Si/sub 3/N/sub 4/ discs and slightly greater than ten for the SiC discs. The thermal resistance at the tube/disc interface was found to decrease significantly with the increased surface contact area due to hand lapping the tube into the disc seat. This resulted in significantly increasing the thermal gradient across the disc, which in turn produced higher stresses in the discs. The parametric Weibull analysis and proven properties of high-performance hot pressed Si/sub 3/N/sub 4/ indicate that the BMSR can have high probability of success (i.e., greater than 93 percent) when Si/sub 3/N/sub 4/ discs with a Weibull modulus of ten are used, even when the thermal contact resistance at the tube disc interface is reduced to zero. A very significant increase in the BMSR reliability can be achieved through extensive inspection, quality control, and proof testing of all the ceramic components. A proof test plan was developed to allow proof testing of Si/sub 3/N/sub 4/ discs to yield a total disc reliability of greater than 99 percent.
- Research Organization:
- AiResearch Mfg. Co., Torrance, CA (USA)
- OSTI ID:
- 5353159
- Report Number(s):
- EPRI-AP-2267; ON: DE82901870
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
140700* -- Solar Thermal Power Systems
141000 -- Solar Collectors & Concentrators
BENCH-SCALE EXPERIMENTS
CARBIDES
CARBON COMPOUNDS
CERAMICS
COMPUTER CODES
DESIGN
FAILURES
HEAT EXCHANGERS
INSPECTION
INTERFACES
NITRIDES
NITROGEN COMPOUNDS
PNICTIDES
POWER RANGE 100-1000 KW
RELIABILITY
SEALS
SILICON CARBIDES
SILICON COMPOUNDS
SILICON NITRIDES
SOLAR RECEIVERS
STATIC LOADS
STEADY-STATE CONDITIONS
STRESSES
TEMPERATURE GRADIENTS
THERMAL SHOCK
THERMAL STRESSES
TRANSIENTS