Systems and methods for modified Wobbe index control with constant fuel temperature

The present application provides a gas turbine engine system (100) for combusting a flow of fuel (160). The gas turbine engine system (100) may include a combustor (140) and a fuel system (150) for providing the flow of fuel (160) to the combustor (140). The fuel system (150) may include a fuel heat exchanger (230) so as to provide the flow of fuel (160) to the combustor (140) at a substantially constant temperature.