Impact of Total Temperature Probe of Geometry on Sensor Flow and Heat Transfer

Abstract

The measurement of temperature in hot gases plays an important role in many engineering applications, such as the efficiency and performance of an engine. As such, understanding the accuracy of these temperature measurements is also important. One of the common ways in which temperature is measured is through the use of total temperature probes. Previous research both at Virginia Tech and in outside studies has been performed to quantify the errors associated with total temperature probe measurements. This work has led to the development of low-order models which can be used to calculate the performance of a total temperature probe as a first-order estimate. These low-order models require knowledge of the heat transfer to the total temperature sensor in order to calculate the probe performance. However, the heat transfer to the sensor is a difficult quantity to calculate and has only been quantified over a set range of operating conditions for a single probe design. This research seeks to expand the range of applicability of the Virginia Tech low-order model by quantifying the heat transfer to the sensor of a total temperature probe over a range of probe geometries through the use of computational models. Key geometry parameters were altered to understand how altering these geometry features would impact the heat transfer to the sensor. In order to quantify the heat transfer to the sensor for varied probe geometries, a new method of characterizing the flow conditions about the sensor was also developed. By characterizing the flow conditions about the sensor, a better quantification of the heat transfer can be obtained. This thesis presents the correlation that was developed to quantify the changes in the flow about the sensor caused by varying the key geometry parameters. The flow conditions encompassed total temperatures from 294 K to 727 K at a Mach number of 0.4. The changes in the flow conditions about the sensor are then used to develop a heat transfer correlation to allow the heat transfer to the sensor to be calculated based off the changes in the flow conditions. The heat transfer to the sensor can then be substituted into the low-order model and used to calculate the performance of a total temperature probe.