Method and system for cooling of engine mounted components
A cooling system includes a fuel supply system and a cooling fuel path. The fuel supply system includes a boost stage pump and a main stage pump, while the cooling fuel path includes a fuel bleed from an outlet of the boost stage pump, a fuel return to an inlet of the boost stage pump, and a cooler disposed fluidly between the fuel bleed and the fuel return.
1 . A cooling system for a gas turbine engine, the cooling system comprising:
a fuel supply system comprising:
a boost stage pump disposed to receive and pressurize a fuel from a fuel source, with the pressurization increasing as a function of a speed of the gas turbine engine;
a main stage pump disposed downstream of the boost stage pump, and configured to further pressurize a first portion of the fuel for injection and subsequent combustion;
a fuel control system actuatable to control injection of the first portion of the fuel from the main stage pump into a combustor of the gas turbine engine; and
a fuel heat exchanger disposed to use the first portion of the fuel as a first cooling fluid; and
a cooling fuel path comprising:
a fuel bleed from an outlet of the boost stage pump, the fuel bleed located upstream of the main stage pump;
a cooler fluidly connected to receive a second portion of the fuel from the fuel bleed as a second cooling fluid;
a fuel return fluidly connecting a downstream side of the cooler to an inlet of the boost stage pump; and
a 3-way thermal valve disposed between the fuel bleed and the cooler, and having an input downstream of the fuel heat exchanger,
wherein the 3-way thermal valve is operable between two modes:
a first mode fluidly connecting the fuel bleed to the cooler, excluding the fuel heat exchanger; and
a second mode disconnecting the fuel bleed from direct fluid communication with the cooler, and fluidly connecting the cooler to receive at least a portion of the second portion of the fuel output from the fuel heat exchanger.
2 . The cooling system of claim 1 , wherein the boost stage pump is a centrifugal pump with pump speed and consequently pump pressure dependent on the speed of the gas turbine engine.
3 . The cooling system of claim 1 , wherein the fuel supply system further comprises a debris filter, and wherein the debris filter and the fuel heat exchanger are situated downstream of the boost stage pump and upstream of the main stage pump.
4 . The cooling system of claim 3 , wherein the input of the 3-way thermal valve is disposed downstream of the debris filter.
5 . The cooling system of claim 1 , wherein the cooling fuel path further comprises a check valve disposed between the 3-way thermal valve and the main stage pump, to prevent the at least a portion of the second portion of the fuel flow from the 3-way thermal valve to the main stage pump by bypassing the fuel heat exchanger and a debris filter.
6 . The cooling system of claim 1 , wherein actuation of the 3-way thermal valve between the two modes is based on a temperature of at least one of the first portion of the fuel and the at least a portion of the second portion of the fuel.
7 . The cooling system of claim 6 , wherein the 3-way thermal valve is a passive valve responsive to the temperature of at least one of the first portion of the fuel and the at least a portion of the second portion of the fuel delivered to the 3-way thermal valve.
8 . The cooling system of claim 7 , wherein the 3-way thermal valve comprises a shape-memory alloy spring, a bimetallic disk stack, and/or a thermal wax.
9 . The cooling system of claim 6 , wherein the 3-way thermal valve is an electrically actuated valve controlled based on the temperature of at least one of the first portion of the fuel and the at least a portion of the second portion of the fuel.
10 . The cooling system of claim 9 , further comprising a fuel temperature sensor disposed along a fluid path of fluid between the boost stage pump and the fuel control system to sense a fuel temperature indicating at least one of the first portion of the fuel and the at least a portion of the second portion of the fuel.
11 . The cooling system of claim 10 , wherein the fuel temperature sensor is disposed downstream of the main stage pump.
12 . The cooling system of claim 10 , wherein the fuel temperature sensor is disposed upstream of the fuel heat exchanger, downstream of the boost stage pressure pump.
13 . The cooling system of claim 10 , wherein the fuel temperature sensor is disposed downstream of the fuel heat exchanger, upstream of the main stage pump.
14 . The cooling system of claim 6 , wherein the actuation of the 3-way thermal valve based on the temperature of at least one of the first portion of the fuel and the at least a portion of the second portion of the fuel further comprising: causing the valve causes the 3-way thermal valve to operate in the second mode when the fuel temperature of the at least a portion of the second portion of the fuel is below an overheat threshold temperature.
15 . The cooling system of claim 6 , wherein the actuation of the 3-way thermal valve based on the temperature of at least one of the first portion of the fuel and the at least a portion of the second portion of the fuel further comprising: causing the valve causes the 3-way thermal valve to operate in the first mode when the fuel temperature of the first portion of the fuel is above an anti-icing threshold temperature.
16 . The cooling system of claim 1 , further comprising an additional cooled component serially disposed downstream of the cooler, upstream of the fuel return.