A system and method of an airflow control system for a vehicle is described herein. The airflow control system (100) includes an airflow housing (120) defining an airflow passageway (125) extending between a bypass opening (122) and an intake outlet (124). The airflow housing also defines a duct opening (126) positioned between the bypass opening (122) and the intake outlet (124). The intake outlet (124) may be in fluid communication with an engine intake (12) of the vehicle such that air passes from the bypass opening (122) and/or the duct opening (126) to the engine intake (12). The airflow control system (100) also includes a movable duct (160) movably connected to the airflow housing (120) to selectively allow or prevent air passage through the duct opening (126) and into the engine intake (12), and further includes a bypass door (140) movably connected to the airflow housing (120) to selectively allow or prevent air passage through the bypass opening (122) and into the engine intake (12).

A system and method of an airflow control system for a vehicle is described herein. The airflow control system (100) includes an airflow housing (120) defining an airflow passageway (125) extending between a bypass opening (122) and an intake outlet (124). The airflow housing also defines a duct opening (126) positioned between the bypass opening (122) and the intake outlet (124). The intake outlet (124) may be in fluid communication with an engine intake (12) of the vehicle such that air passes from the bypass opening (122) and/or the duct opening (126) to the engine intake (12). The airflow control system (100) also includes a movable duct (160) movably connected to the airflow housing (120) to selectively allow or prevent air passage through the duct opening (126) and into the engine intake (12), and further includes a bypass door (140) movably connected to the airflow housing (120) to selectively allow or prevent air passage through the bypass opening (122) and into the engine intake (12).

The method can include sensing operating conditions of the gas turbine engine; generating a base value signal of a control parameter of the bleed valve based on the sensed operating conditions and on control data; determining whether a contaminant management condition is met; generating a control value signal of the control parameter including the base value signal and, when the contaminant management conditions is met, the control value signal further including a contaminant management signal of the control parameter value of the valve superposed to the base value signal, the contaminant management signal including at least three successive back and forth fluctuations of the control parameter value relative the base value signal over a period of 10 seconds or less; and controlling an actuator of the bleed valve based on the control value signal.

The method can include sensing operating conditions of the gas turbine engine; generating a base value signal of a control parameter of the bleed valve based on the sensed operating conditions and on control data; determining whether a contaminant management condition is met; generating a control value signal of the control parameter including the base value signal and, when the contaminant management conditions is met, the control value signal further including a contaminant management signal of the control parameter value of the valve superposed to the base value signal, the contaminant management signal including at least three successive back and forth fluctuations of the control parameter value relative the base value signal over a period of 10 seconds or less; and controlling an actuator of the bleed valve based on the control value signal.

An air intake system for an aircraft, which is switchable between a performance mode and a filtered mode, includes a duct forming filtered air inlet slits. The air intake system also includes interconnected gills adjacent to the filtered air inlet slits. The gills are movable between various gill positions including a closed position substantially covering the filtered air inlet slits and an open position substantially exposing the filtered air inlet slits. The air intake system also includes an actuator configured to move the gills into the closed position in the performance mode and the open position in the filtered mode.

An air intake system for an aircraft, which is switchable between a performance mode and a filtered mode, includes a duct forming filtered air inlet slits. The air intake system also includes interconnected gills adjacent to the filtered air inlet slits. The gills are movable between various gill positions including a closed position substantially covering the filtered air inlet slits and an open position substantially exposing the filtered air inlet slits. The air intake system also includes an actuator configured to move the gills into the closed position in the performance mode and the open position in the filtered mode.

A method for inhibiting particulate ingress in a combustion system includes acquiring particulate ingress data, determining a probable particulate ingress location on an air inlet of the combustion system in dependence upon the particulate ingress data, and deploying a filter screen at the determined probable particulate ingress location to inhibit particulate ingress at the determined probable particulate ingress location.

Systems and methods for adjusting a variable geometry mechanism of an engine are described herein. An engine control request indicative of a desired output power for the engine is monitored. A rate of change of the engine control request is determined. The rate of change is compared to a threshold. Responsive to determining that the rate of change is beyond the threshold, a transient bias map is applied to a steady-state schedule to generate a variable geometry mechanism request indicative of a target position for the variable geometry mechanism. The variable geometry mechanism is adjusted toward the target position according to the variable geometry mechanism request.

Systems and methods to increase intake air flow to a gas turbine engine of a hydraulic fracturing unit when positioned in an enclosure may include providing an intake expansion assembly to enhance intake air flow to the gas turbine engine. The intake expansion assembly may include an intake expansion wall defining a plurality of intake ports positioned to supply intake air to the gas turbine engine. The intake expansion assembly also may include one or more actuators connected to a main housing of the enclosure and the intake expansion assembly. The one or more actuators may be positioned to cause the intake expansion wall to move relative to the main housing between a first position preventing air flow through the plurality of intake ports and a second position providing air flow through the plurality of intake ports to an interior of the enclosure.

Systems and methods to increase intake air flow to a gas turbine engine of a hydraulic fracturing unit when positioned in an enclosure may include providing an intake expansion assembly to enhance intake air flow to the gas turbine engine. The intake expansion assembly may include an intake expansion wall defining a plurality of intake ports positioned to supply intake air to the gas turbine engine. The intake expansion assembly also may include one or more actuators connected to a main housing of the enclosure and the intake expansion assembly. The one or more actuators may be positioned to cause the intake expansion wall to move relative to the main housing between a first position preventing air flow through the plurality of intake ports and a second position providing air flow through the plurality of intake ports to an interior of the enclosure.