The thermal-structural response and low cycle fatigue life of a three-dimensional (3D) channel wall nozzle with regenerative cooling were numerically investigated by coupling the finite volume fluid-thermal method

nonlinear finite element thermal-structural analysis and local strain methods. The nozzle had a high area ratio (nozzle exit area divided by throat area) under cyclic working loads. Parametric studies were carried out to evaluate the effects of channel structural parameters such as channel width

channel height

liner thickness and rib width. Results showed that the integrated effects of three-dimensional channel structure and load distribution caused serious strain

which mainly occurred at the intersectant regions of liner wall on the gas side and the symmetric planes of channel and rib. The cooling effect and channel structural strength were significantly improved as the channel width and height decreased

leading to substantial extension of the nozzle service life. On the other hand

the successive decrease in liner thickness and rib width apparently increased the strain amplitude and residual strain of channel wall nozzle during cyclic work

significantly shortening the service life. The present work is of value for design of the channel wall nozzle to prolong its cyclic service life.