An air bottoming cycle (ABC) was proposed in the 1980 decade as an alternative for the conventional steam bottoming cycle. Now this cycle is being applied as a compact and simple bottoming cycle. In the gas-air heat exchanger, thermal energy of topping cycle exhaust is transferred to bottoming cycle. In fact, exhaust of topping cycle is using as a heat source for bottoming cycle. Nevertheless, lower efficiency than combined steam turbine cycles makes ABC not customary. On the other hand, attempt to increase efficiency in gas turbine was leading to wet cycles. Steam was entering in the middle parts of the cycle (between compressor and turbine).Constant compressor consuming work and increasing in turbine work is the main reason for high efficiency. In this paper, steam injection in ABC is investigated while efficiency increases and we exploit both cycle benefits (steam injection and ABS).In fact, our innovation is using combination of air bottoming and wet cycles for heat recovery purpose. Steam injecting is possible in two forms in the ABC. First is using the topping cycle exhaust energy to change water in to steam, then injected in the mixer which is located after compressor of bottoming cycle (STI-ABC). This steam is mixing with hot air that is leaving the compressor. In the second method, water is injected in the ABC compressor outlet (evaporator) directly, and water evaporates when contacts with the hot air (E-ABC). The Temperature of mixture is reduced so, heat recovery in the gas-air heat exchanger (regenerator or recuperator) is improving. These cycles were modeling and a code was prepared for each one, for the purpose of calculating desired parameters. Decreasing corrosion (in comparison with wet cycles) and reducing undesirable effect of ambient temperature on efficiency of combined ABC cycle are advantages of using STI-ABC and E-ABC. In addition, overall efficiency is increasing about 10-12 percent than simple gas turbine and 2.5-3.5 percent than combined ABC cycle.

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