Abstract: An aircraft includes a machine body that encloses a turbofan gas turbine engine and a plurality of ancillary systems. The turbofan gas turbine engine includes, in axial flow sequence, a first heat exchanger module, a fan assembly, a compressor module, a combustor module, a turbine module, and an exhaust module. The aircraft includes a second heat exchanger module. The machine body comprises a single fluid inlet aperture, with the fluid inlet aperture being configured to allow a fluid cooling flow to enter the machine body and to pass through the first heat exchanger module. When a temperature of the fluid cooling flow is less than a temperature of a fluid to be cooled, the fluid to be cooled is directed to the first heat exchanger module, and when a temperature of the fluid cooling flow is greater than a temperature of the fluid to be cooled, the fluid to be cooled is directed to the second heat exchanger module and cooled using a fuel supply for the gas turbine engine.

Abstract: A turbofan gas turbine engine comprises, in axial flow sequence, a heat exchanger module, a fan assembly, a compressor module, and a turbine module. The fan assembly comprises a plurality of fan blades defining a fan diameter (D). The heat exchanger module comprises a plurality of heat transfer elements. The heat exchanger module is in fluid communication with the fan assembly by an inlet duct. The inlet duct has a fluid path length along a central axis of the inlet duct between a downstream-most face of the heat transfer elements and an upstream-most face of the fan assembly. The fluid path length is less than 10.0*D.

Abstract: A turbofan gas turbine engine includes, in axial flow sequence, a heat exchanger module, a fan assembly, a compressor module, and a turbine module. The fan assembly includes a plurality of fan blades defining a fan diameter, and the heat exchanger module is in fluid communication with the fan assembly by an inlet duct. The heat exchanger module includes a plurality of heat transfer elements for transfer of heat from a first fluid contained within the heat transfer elements to an airflow passing over a surface of the heat transfer elements prior to entry of the airflow into an inlet to the fan assembly. At full-power condition, the engine produces a maximum thrust T (N), the heat exchanger module transfers a maximum heat rejection H (W) from the first fluid to the airflow, and a Heat Exchanger Performance parameter PEX (W/N) defined as PEX=H/T is 0.4 to 6.0.

Abstract: A turbofan gas turbine engine includes, in axial flow sequence, a heat exchanger module, a fan assembly, a compressor module, and a turbine module. The fan assembly includes fan blades defining a corresponding fan area (AFAN). The heat exchanger module is in fluid communication with the fan assembly by an inlet duct, and includes radially-extending vanes arranged in a circumferential array with at least one vane including a heat transfer element for heat transfer from a first fluid contained within each element to an airflow passing over a surface of each heat transfer element before entering the fan assembly inlet. Each heat transfer element extends axially along the corresponding vane, with a swept heat transfer element area (AHTE) being the wetted surface area of all heat transfer elements in contact with the airflow. A Fan to Element Area parameter FEA of AHTE/AFAN lies in the range of 47 to 132.

Abstract: An aircraft includes a machine body that encloses a turbofan gas turbine engine and a plurality of ancillary systems. The turbofan gas turbine engine includes, in axial flow sequence, a first heat exchanger module, a fan assembly, a compressor module, a combustor module, a turbine module, and an exhaust module. The aircraft includes a second heat exchanger module. The machine body comprises a single fluid inlet aperture, with the fluid inlet aperture being configured to allow a fluid cooling flow to enter the machine body and to pass through the first heat exchanger module. When a temperature of the fluid cooling flow is less than a temperature of a fluid to be cooled, the fluid to be cooled is directed to the first heat exchanger module, and when a temperature of the fluid cooling flow is greater than a temperature of the fluid to be cooled, the fluid to be cooled is directed to the second heat exchanger module and cooled using a fuel supply for the gas turbine engine.

Abstract: A turbofan gas turbine engine comprises, in axial flow sequence, a heat exchanger module, an inlet duct, a fan assembly, a compressor module, and a turbine module. The fan assembly comprises a plurality of fan blades defining a fan diameter D, and the heat exchanger module comprises a plurality of heat transfer elements for transfer of heat from a first fluid contained within the heat transfer elements to an airflow passing over a surface of the heat transfer elements prior to entry of the airflow into the fan assembly. In use, the first fluid has a maximum temperature of 80° C., and the heat exchanger module transfers at least 300 kW of heat energy from the first fluid to the airflow.

Abstract: An aircraft gas turbine engine includes a heat exchanger module, and a core engine including an intermediate-pressure compressor, a high-pressure compressor, a high pressure turbine, and a low-pressure turbine. The high-pressure compressor is connected to the high-pressure turbine by a first shaft, and the intermediate-pressure compressor is connected to the low-pressure turbine by a second shaft. The heat exchanger module includes a central hub and heat transfer elements extending radially from the central hub and spaced in a circumferential array, for transferring heat energy from a fluid within the heat transfer elements to an inlet airflow passing over the heat transfer elements prior to entry of the airflow into an inlet to the core engine. The gas turbine engine further includes a first electric machine connected to the first shaft and positioned downstream of the heat exchanger module, and a second electric machines connected to the second shaft.

Abstract: An aircraft comprises a machine body. The machine body encloses a turbofan gas turbine engine and a plurality of ancillary systems. The turbofan gas turbine engine comprises, in axial flow sequence, a heat exchanger module, a fan assembly, a compressor module, a combustor module, a turbine module, and an exhaust module. The machine body comprises a single fluid inlet aperture, with the fluid inlet aperture being configured to allow a fluid cooling flow to enter the machine body and to pass through the heat exchanger module. The heat exchanger module is configured to transfer a waste heat load from the gas turbine engine and the ancillary systems to the fluid cooling flow prior to an entry of the entire fluid cooling flow into the fan module.

Abstract: A turbofan gas turbine engine includes, in axial flow sequence, a heat exchanger module, a fan assembly, a compressor module, a turbine module, and an exhaust module. The fan assembly includes fan blades defining a fan diameter. The heat exchanger module is in communication with the fan assembly by an inlet duct, and the heat exchanger module further includes radially-extending hollow vanes arranged in a circumferential array, with a channel extending axially between hollow vanes. Each hollow vane accommodates at least one heat transfer element to transfer heat from a first fluid contained within the or each heat transfer element to a corresponding vane airflow passing through the hollow vane and over a surface of the or each heat transfer element. Each hollow vane further includes a flow modulator configured to regulate airflow in proportion to total airflow entering the heat exchanger module in response to a user requirement.

Abstract: A turbofan gas turbine engine includes, in axial flow sequence, a heat exchanger module, a fan assembly, a compressor module, a turbine module, and an exhaust module. The fan assembly includes a plurality of fan blades defining a fan diameter (D). The heat exchanger module is in fluid communication with the fan assembly by an inlet duct, and the heat exchanger module includes a plurality of radially-extending hollow vanes arranged in a circumferential array with a channel extending axially between each pair of adjacent hollow vanes. An airflow entering the heat exchanger module is divided between a set of vane airflows through each of the hollow vanes and a set of channel airflows through each of the channels.

Abstract: A turbofan gas turbine engine includes, in axial flow sequence, a heat exchanger module, a fan assembly, a compressor module, a turbine module, and an exhaust module. The fan assembly includes a plurality of fan blades defining a fan diameter. The heat exchanger module is in fluid communication with the fan assembly by an inlet duct, and the heat exchanger module including a plurality of heat transfer elements for transfer of heat from a first fluid contained within the heat transfer elements to an airflow passing over a surface of the heat transfer elements prior to entry of the airflow into an inlet to the fan assembly. Each heat transfer element may be individually and independently fluidly isolated from the remaining heat transfer elements.

Abstract: A method of controlling a gas turbine engine includes the steps of: detecting a shaft break event in a shaft connecting a compressor of the gas turbine engine to a turbine of the gas turbine engine; and in response to this detection, activating a shaft break mitigation system which introduces a fluid into a gas flow of the gas turbine engine downstream of the turbine, or increases an amount of a fluid being provided into the gas flow of the gas turbine engine downstream of the turbine, whereby the fluid reduces an effective area of a nozzle for the gas flow so as to reduce the mass flow rate of the gas flow through the turbine.

Abstract: A turbofan gas turbine engine includes heat exchanger module, fan assembly, compressor, turbine and exhaust modules. The fan includes a plurality of fan blades. The heat exchanger in fluid communicates with the fan assembly by an inlet duct, and the heat exchanger includes a plurality of radially-extending hollow vanes arranged in a circumferential array, with a channel extending axially between each pair of adjacent hollow vanes. An airflow entering the heat exchanger is divided between a set of vane airflows and a set of channel airflows. Each vane airflow has a vane mass flow rate FlowVane, and each channel air flow has a channel mass flow rate FlowChan. Each hollow vane includes, an inlet, heat transfer, and exhaust portions, with the inlet portion comprising a diffuser element and the heat transfer portion including at least one heat transfer element. The diffuser element causes FlowVane to be lower than FlowChan.

Abstract: A method is provided of controlling a gas turbine having a shaft connecting a compressor to a turbine, as well as having a reheat system, and a gas turbine. The method includes the steps of: operating the engine using the reheat system to provide a mass flow rate of reheat fuel into a gas flow of the gas turbine engine downstream of an exit of the turbine; detecting a shaft break event in the shaft; and in response to this detection, maintaining the mass flow rate of the reheat fuel being provided into the gas flow downstream of the turbine exit, whereby the maintained mass flow rate of reheat fuel raises a back pressure downstream of the turbine and thereby reduces a rotational speed of the turbine.

Abstract: An aircraft comprises a machine body. The machine body encloses a turbofan gas turbine engine and a plurality of ancillary systems. The turbofan gas turbine engine comprises, in axial flow sequence, a heat exchanger module, a fan assembly, a compressor module, a turbine module, a combustor module, and an exhaust module. The machine body comprises either one or two fluid inlet apertures. The or each fluid inlet aperture is configured to allow a fluid flow to enter the machine body and to pass through the heat exchanger module. The heat exchanger module is configured to transfer a waste heat load from the gas turbine engine and the ancillary systems to the fluid flow prior to an entry of the fluid flow into the fan module, and thence into the compressor module, the turbine module, the combustor module, and the exhaust module.

Abstract: A turbofan gas turbine engine includes, in axial flow sequence, a heat exchanger module, a fan assembly, a compressor module, a turbine module, and an exhaust module. The fan assembly includes a plurality of fan blades defining a fan diameter (D). The heat exchanger module is in fluid communication with the fan assembly by an inlet duct, and the heat exchanger module includes a plurality of radially-extending hollow vanes arranged in a circumferential array with a channel extending axially between each pair of adjacent hollow vanes. An airflow entering the heat exchanger module is divided between a set of vane airflows through each of the hollow vanes and a set of channel airflows through each of the channels.

Abstract: A turbofan gas turbine engine includes, in axial flow sequence, a heat exchanger module, a fan assembly, a compressor module, and a turbine module. The fan assembly includes a plurality of fan blades defining a fan diameter, and the heat exchanger module is in fluid communication with the fan assembly by an inlet duct. The heat exchanger module includes a plurality of heat transfer elements for transfer of heat from a first fluid contained within the heat transfer elements to an airflow passing over a surface of the heat transfer elements prior to entry of the airflow into an inlet to the fan assembly. At full-power condition, the engine produces a maximum thrust T (N), the heat exchanger module transfers a maximum heat rejection H (W) from the first fluid to the airflow, and a Heat Exchanger Performance parameter PEX (W/N) defined as PEX=H/T is 0.4 to 6.0.

Abstract: A turbofan gas turbine engine includes, in axial flow sequence, a heat exchanger module, a fan assembly, a compressor module, a turbine module, and an exhaust module. The fan assembly includes a plurality of fan blades defining a fan diameter. The heat exchanger module is in fluid communication with the fan assembly by an inlet duct, and the heat exchanger module including a plurality of heat transfer elements for transfer of heat from a first fluid contained within the heat transfer elements to an airflow passing over a surface of the heat transfer elements prior to entry of the airflow into an inlet to the fan assembly. Each heat transfer element may be individually and independently fluidly isolated from the remaining heat transfer elements.

Abstract: An aircraft comprises a machine body which encloses a turbofan gas turbine engine. The turbofan gas turbine engine includes a heat exchanger module, fan assembly, compressor module, turbine module, and exhaust module. The heat exchanger module communicates with the fan assembly by an inlet duct. The heat exchanger module includes first heat transfer elements that transfer heat energy from a first fluid within the transfer elements to an airflow passing over a surface of the transfer elements before entry of the airflow into a fan assembly inlet. The first fluid contained within transfer elements has a temperature, and the airflow passing over the transfer element surface has a temperature. The turbofan gas turbine engine further includes at least one second heat transfer element, with the or each second heat transfer element transfers heat energy from the first fluid to a second fluid.

Abstract: A turbofan gas turbine engine comprises, in axial flow sequence, a heat exchanger module, a fan assembly, a compressor module, and a turbine module. The fan assembly comprises a plurality of fan blades defining a fan diameter (D). The heat exchanger module comprises a plurality of heat transfer elements. The heat exchanger module is in fluid communication with the fan assembly by an inlet duct. The inlet duct has a fluid path length along a central axis of the inlet duct between a downstream-most face of the heat transfer elements and an upstream-most face of the fan assembly. The fluid path length is less than 10.0*D.