Liquid fluid systems for turbine engines
A method of operating a thermal management system associated with a turbine engine includes circulating a pericritical fluid through a cooling circuit; generating a sensor output using a phase detection sensor in fluid communication with the pericritical fluid, the sensor output including an impedance value; determining that the pericritical fluid has reached a bubble point based at least on a first characteristic change in the impedance value; determining that the pericritical fluid has reached a dew point based at least on a second characteristic change in the impedance value, the second characteristic change being different from the first characteristic change; and controlling at least one controllable component of the thermal management system based at least on the bubble point and the dew point.
1 . A method of operating a thermal management system associated with a turbine engine, the method comprising:
circulating a pericritical fluid through a cooling circuit;
generating a sensor output using a phase detection sensor in fluid communication with the pericritical fluid, the sensor output including an impedance value;
determining that the pericritical fluid has reached a bubble point based at least on a first characteristic change in the impedance value;
determining that the pericritical fluid has reached a dew point based at least on a second characteristic change in the impedance value, the second characteristic change being different from the first characteristic change; and
controlling at least one controllable component of the thermal management system based at least on the bubble point and the dew point.
2 . The method of claim 1 , wherein the first characteristic change comprises an increase in the impedance value by a first amount, and wherein the second characteristic change comprises an increase in the impedance value by a second amount that is greater than the first amount.
3 . The method of claim 1 , further comprising determining that the impedance value is above an upper threshold value, below a lower threshold value, or within a range between the upper threshold value and the lower threshold value.
4 . The method of claim 1 , further comprising determining that a rate of change of the impedance value is above an upper threshold rate of change value or below a lower threshold rate of change value.
5 . The method of claim 1 , further comprising determining that the pericritical fluid has reached a critical point when the impedance value is about zero.
6 . The method of claim 1 , wherein the impedance value exhibits multiple inflection points, and wherein the multiple inflection points correspond to a component part of a bimodal fluid or a component part of a multimodal fluid.
7 . The method of claim 1 , further comprising determining one or more additional phase properties of the pericritical fluid based on the sensor output and at least one of a look-up table or a model.
8 . A pericritical fluid system for a thermal management system associated with a turbine engine, the pericritical fluid system comprising:
a cooling circuit configured to circulate a pericritical fluid;
a phase detection sensor configured to generate a sensor output including an impedance value corresponding to the pericritical fluid; and
a controller communicatively coupled to the phase detection sensor, the controller configured to:
determine that the pericritical fluid has reached a bubble point based at least on a first characteristic change in the impedance value;
determine that the pericritical fluid has reached a dew point based at least on a second characteristic change in the impedance value, the second characteristic change being different from the first characteristic change; and
control at least one controllable component of the thermal management system based at least on the bubble point and the dew point.
9 . The pericritical fluid system of claim 8 , wherein the controller is further configured to determine that the first characteristic change comprises an increase in the impedance value by a first amount and that the second characteristic change comprises an increase in the impedance value by a second amount that is greater than the first amount.
10 . The pericritical fluid system of claim 8 , wherein the controller is further configured to determine that the pericritical fluid has reached a critical point based at least on the impedance value being about zero.
11 . The pericritical fluid system of claim 8 , further comprising a second phase detection sensor configured to generate a second sensor output, wherein the controller is configured to determine a phase separation condition of the pericritical fluid based at least on a level of noise or a deviation in the second sensor output.
12 . The pericritical fluid system of claim 11 , wherein the second phase detection sensor comprises a fiber-optic reflectometer.
13 . The pericritical fluid system of claim 11 , wherein the controller is further configured to determine that the level of noise or the deviation increases as a result of phase separation.
14 . The pericritical fluid system of claim 8 , wherein the cooling circuit is configured as a thermal transport bus comprising a plurality of heat exchangers respectively configured to transfer heat from a plurality of fluid streams to the pericritical fluid.
15 . The pericritical fluid system of claim 14 , wherein the plurality of heat exchangers include at least one of: a fuel system heat exchanger, a lubrication system heat exchanger, a sump heat exchanger, a bleed air heat exchanger, a compressor cooling air heat exchanger, a thermal clearance control heat exchanger, an engine casing heat exchanger, an environmental control system heat exchanger, or an auxiliary systems heat exchanger.
16 . The pericritical fluid system of claim 8 , wherein the thermal management system comprises a primary cooling circuit and an intermediate cooling circuit with an intermediate heat exchanger configured to transfer heat from a primary cooling fluid to an intermediate cooling fluid, and wherein the intermediate cooling fluid is supplied in a supercritical phase state or a near-supercritical phase state.
17 . A non-transitory computer-readable medium storing instructions that, when executed by one or more processors of a controller for a thermal management system associated with a turbine engine, cause the controller to:
receive a sensor output from a phase detection sensor in fluid communication with a pericritical fluid circulating through a cooling circuit, the sensor output including an impedance value;
determine that the pericritical fluid has reached a bubble point based at least on a first characteristic change in the impedance value;
determine that the pericritical fluid has reached a dew point based at least on a second characteristic change in the impedance value, the second characteristic change being different from the first characteristic change; and
output a control signal to control at least one controllable component of the thermal management system based at least on the bubble point and the dew point.
18 . The non-transitory computer-readable medium of claim 17 , wherein the first characteristic change comprises an increase in the impedance value by a first amount, and wherein the second characteristic change comprises an increase in the impedance value by a second amount that is greater than the first amount.
19 . The non-transitory computer-readable medium of claim 17 , wherein the instructions, when executed by the one or more processors of the controller for the thermal management system associated with the turbine engine, further cause the controller to:
determine that the pericritical fluid has reached a critical point when the impedance value is about zero.
20 . The non-transitory computer-readable medium of claim 17 , wherein the instructions, when executed by the one or more processors of the controller for the thermal management system associated with the turbine engine, further cause the controller to:
determine a phase separation condition based at least on a level of noise or a deviation in a second sensor output from a second phase detection sensor.