Paper presented at the 8th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Mauritius, 11-13 July, 2011.
Investigating the heat transfer inside internal combustion
engines is key in the search for higher efficiency, higher power
output and lower emissions. To understand the process and to
validate model predictions, heat flux measurements inside an
engine have to be conducted. In previous works, we have
always used a commercially available thermopile to measure
the heat transfer in a hydrogen combustion engine, but its large
dimensions pose concerns about the sensor’s response time.
Therefore, measurements have been done on a calibration rig
with a hot air flow as heat source. This paper presents a
comparison of the rise time of the thermopile with that of an
alternative sensor developed for heat transfer measurements in
gas turbines. The papers results in an increased confidence in
the thermopile sensor, because its response time is at least as
good as that of the alternative sensor. The results do show that
the reproducibility of the test rig can be improved. Moreover,
due to fluctuations in the heat flux level generated by the
source, only the order of magnitude of the measured heat flux
of two different experiments was comparable. Therefore, a new
calibration rig will be developed to improve the reproducibility
and to increase stability of the heat flux level of the heat source.
