Development of Gas Dynamic Probe for High Total Temperature Measurement in High Speed Flow

[摘要] Total temperature measurement in high speed and high temperature exhaust of air breathing engines like scramjet, ramjet and turbojets with afterburner is a challenging problem. The temperature of such hot gases is approximately 2000-2200 K. Conventional technique of temperature measurement by thermocouple suffers oxidation, doesn't withstand aerodynamic load, and lacks robustness. Unconventional technique like optical method is expensive. These limitations have withheld the temperature measurement in high speed high temperature exhaust streams. Present work describes the design and development of a water cooled gas dynamic probe for total temperature measurement of high speed and high temperature gases. The probe consists of two choked nozzles in series. The hot flow is cooled after passing through the first nozzle, in a small settling chamber, using a heat exchanger. The flow from settling chamber is accelerated to Mach 1 in second nozzle. Using gas dynamic relations and measured parameters, the incoming flow total temperature is obtained. The probe has been calibrated for probe constant at total temperature range of 1200 to 1700 K at inlet Mach number 2. Probe constant varies proportional to the square of incoming flow total temperature. First restriction with C-D nozzle gave higher probe constant value than convergent nozzle.

[发布机构] Propulsion Division, NWTC, CSIR, National Aerospace Laboratories, Bangalore, Karnataka, India^1;Graduate, IIAEM, Jain University, Bangalore, Karnataka, India^2

[效力级别] 机械制造

[关键词] Air breathing engines;Conventional techniques;Convergent nozzles;Design and Development;High temperature;Measured parameters;Settling chambers;Total temperatures