Null Point Calorimeter Sweeps with Comparisons to Thermal FEA Model Predictions

Santos, José Maria Campos dos; Oishi, Tomo; Martinez, Edward

doi:10.2514/6.2009-3758

Cited by 4 publications

(1 citation statement)

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“…The thermal energy is determined by obtaining a temperature measurement at the back surface of the element, and the rate of change of the temperature provides the heat flux of the exposed surface. Different types of calorimeter gauges, such as thin-wall calorimeters [14], slug calorimeters [27], and null-point calorimeters [28,29], have been developed by researchers to address the requirements of unique testing environments. Slug and null-point calorimeter gauges are generally developed for long test time measurements (such as a plasma wind tunnel), whereas a thin-wall calorimeter is more suitable for transient hypersonic facilities with testing durations on the order of milliseconds.…”

Section: Introductionmentioning

confidence: 99%

A Fast-Response Calorimeter with Dynamic Corrections for Transient Heat Transfer Measurements

Zhang

Wang

et al. 2020

Applied Sciences

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Robust fast-response transient calorimeters with novel calorimeter elements have attracted the attention of researchers as new synthetic materials have been developed. This sensor uses diamonds as the calorimeter element, and a platinum film resistance is sputtered on the back to measure the temperature. The surface heat flux is obtained based on the calorimetric principle. The sensor has the advantages of high sensitivity and not being prone to erosion. However, non-ideal conditions, such as heat dissipation from the calorimeter element to the surroundings, can lead to measurement deviation and result in challenges for sensor miniaturization. In this study, a novel transient calorimeter (NTC) with two different sizes was developed using air or epoxy as the back-filling material. Numerical simulations were conducted to explain the complex heat exchange between the calorimeter element and its surroundings, which showed that it deviated from the assumption of an ideal calorimeter sensor. Accordingly, a dynamic correction method was proposed to compensate for the energy loss from the backside of the calorimeter element. The numerical results showed that the dynamic correction method significantly improved the measurement deviation, and the relative error was within 2.3% if the test time was smaller than 12 ms in the simulated cases. Detonation shock tunnel experiments confirmed the results of the dynamic correction method and demonstrated a practical method to obtain the dynamic correction coefficient. The accuracy and feasibility of the dynamic correction method were verified in a single detonation shock tunnel and under shock tube conditions. The NTC calorimeter exhibited good repeatability in all experiments.

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Section: Introductionmentioning

confidence: 99%