Recuperator in a microturbine system, which must work at high temperature and high pressure, is a key component to improve the electricity efficiency of the system. Creep deformation may occur in the passages of the compact primary sheet with the increase of the operation time. Creep is important in high temperature stress analyses, because over a period of time at high temperature, the preload in the recuperator would decrease (stress relaxation) and potentially let the adjacent parts move. Typically, the creep deformation is permanent. Inside the recuperator creep deformation causes the compressor discharge air passages to expand; thus restrict exhaust gas flow and increase the turbine backpressure. And this has bad effect on the flow and heat transfer performance of the recuperator, even on the safety of the whole system operation. In this paper, with the implicit Norton function supplied by software ANSYS, the creep deformation of cross wavy (CW) recuperators (for 40,000 hours operation) is analyzed to prove the reliability of material and some influencing factors on creep strain are investigated. Five conclusions are obtained: (1) Alloy 0Cr18Ni11Nb is an acceptable material for recuperators. (2) The pressure difference between the air and the gas is the main reason to cause creep deformation of the sheet. (3) The creep resistant alloy with metallic element Nb is good to be used when manufacturing recuperators. (4) The widths of the gas passage must be larger than that of the air passage to balance the deformation of the two sides. (5) A method for finding an optimal thickness is presented. δ = 0.12mm is suggested as the maximum sheet thickness.

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