Off-design performance of simple and recuperation cycles was studied with calculation

analysis and comparison by means of gas turbine modelling technique and the models were solved by Newton-Raphson method.Main conclusions are as follows.Under the same operating parameters

the simple cycle gas turbine can provide more power output than the recuperation cycle one

while the latter is more efficient than the former.The efficiency of the recuperation cycle decreases faster than the counterpart as the turbine inlet temperatures decrease.For both cycles

the power outputs and efficiencies of gas turbines increase

but the compressor surge margins decrease with the drop of ambient temperature.The power outputs

efficiencies and compressor surge margins of gas turbines increase with the rise of ambient pressure.The above conclusions can provide good references for the off-design operation of aero-engine derived land-borne turbine generators.