Methods and systems for measuring atmospheric water content

• US 7,698,927 B2
• Filed: 01/30/2007
• Issued: 04/20/2010
• Est. Priority Date: 01/30/2007
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Tillotson, Brian J., Spinelli, Charles B., Ross, Tamaira E.
• Primary Examiner(s): Williams; Hezron
• Assistant Examiner(s): Frank; Rodney T
• Application Number:
  US11/668,956
• Publication Number:
  US 20080178659A1
• Time in Patent Office: 1,176 Days
• Field of Search: 73/290.1
• US Class Current: 73/29.01
• CPC Class Codes: G01N 25/58 by measuring changes of properties of the material due to heat, cold or expansion
• CPC Class Codes: G01W 1/08 Adaptations of balloons, missiles, or aircraft for meteorological purposes; Radiosondes transmission of measurements G01D; transmitting circuits H04B; balloons in general B64B; aeroplanes in general B64D; missiles in general F42B15/00
• CPC Class Codes: G01W 1/10 Devices for predicting weather conditions computers per se G06; display devices G09

Abstract

Methods and systems for measuring atmospheric water content, are provided. The method includes measuring a first air temperature and a first air pressure at a first location in a compressor, measuring a second air temperature and a second air pressure at a second location in the compressor, computing a ratio of specific heats from the first and second air temperatures and the first and second air pressures, and determining an atmospheric water content from the ratio of specific heats.

Claims

1. A method for measuring atmospheric water content comprising:

measuring a first air temperature and a first air pressure at a first location in a compressor;

measuring a second air temperature and a second air pressure at a second location in the compressor;

computing a ratio of specific heats from the first and second air temperatures and the first and second air pressures; and

determining an atmospheric water content from the ratio of specific heats.

2. A method in accordance with claim 1 wherein the compressor is at least one of a portion of a turbine engine and a supercharger.

3. A method in accordance with claim 1 wherein determining an atmospheric water content comprises assuming ideal gas behavior and isentropic compression.

4. A method in accordance with claim 1 wherein determining an atmospheric water content comprises correcting for non-ideal gas behavior.

5. A method in accordance with claim 1 wherein determining an atmospheric water content comprises correcting for non-isentropic compression.

6. A method in accordance with claim 1 wherein measuring a first air temperature and a first air pressure at a first location comprises measuring a first air temperature and a first air pressure at a first location that is upstream from at least one of the compressor and a compressor stage.

7. A method in accordance with claim 1 wherein measuring a second air temperature and a second air pressure at a second location comprises measuring a second air temperature and a second air pressure at a second location that is downstream from at least one of the compressor and a compressor stage.

8. A method in accordance with claim 1 wherein determining an atmospheric water content from the ratio of specific heats comprises using a look-up table.

9. A method in accordance with claim 1 wherein determining an atmospheric water content from the ratio of specific heats comprises using a look-up table relating a ratio of specific heats to a humidity ratio.

10. A method in accordance with claim 1 further comprising:

recording the time and location of the measurement of at least one of the first air temperature, the second air temperature, the first air pressure, and the second air pressure;

transmitting each of the measurements, the respective time, and the respective location to a weather forecast model, and

executing the weather forecast model to generate a weather forecast using the measurement of at least one of the first air temperature, the second air temperature, the first air pressure, and the second air pressure.

11. A method in accordance with claim 10 further comprising providing the weather forecast model with atmospheric measurements from a plurality of times and locations wherein the additional atmospheric measurements are acquired from other than the compressor.

12. A method of forecasting weather comprising:

determining a specific heat of a volume of air in a gas turbine engine;

determining a water content of the volume of air using the specific heat of the volume of air;

transmitting the specific heat and the water content to a weather forecast model; and

executing the weather forecast model of facilitate generating a weather forecast.

13. A method in accordance with claim 12 wherein determining a specific heat of a volume of air comprises measuring a first air temperature and a first air pressure at a first location.

14. A method in accordance with claim 12 wherein determining a specific heat of a volume of air comprises measuring a second air temperature and a second air pressure at a second location.

15. A method in accordance with claim 12 wherein determining a water content of the volume of air comprises computing a ratio of specific heats from the first and second air temperatures and the first and second air pressures.

16. A method in accordance with claim 12 wherein determining an atmospheric water content from the ratio of specific heats comprises using a lookup table.

17. A method comprising:

determining a specific heat of a volume of air in a gas turbine engine; and

determining an atmospheric water content of the volume of air using the specific heat of the volume of air based upon data in a lookup table.