Error analysis for liquid-vapour phase change experiments

Deshpande, MD and Shankar, PN (1989) Error analysis for liquid-vapour phase change experiments. Technical Report. National Aerospace Laboratories, Bangalore, India.

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Abstract

An error analysis has been made for temperature measurements in liquid-vapour phase change experiments. The temperature distribution in the Thermocouple (TC) wire has been calculated by accounting for the heat fluxes' to get an estimate of the errors. 'In case of measurements in air at low and moderate pressures the heat transfer from air to wire is by conduction whereas, in the case'of measurements in mercury vapour it is by convection. Radiation is accounted for in both the cases. Wherever uncertainties or difficulties are faced in making reasonable assumptions, conservative estimates are made for the errors which should serve as an upper bound. For air at moderate pressures the errors are .in the range of.:t. 0.10 C. These meaurements enhance our,' confidence in the suitability of the apparatus and instrumentation for the phase change experiments. The error bounds for the measurements in mercury are about 10-20 C . Interestingly, apart from being $ma11 compared to.the temperaturejumps observed these error corrections are of the same magnitude for all locations of the TCs and hence the measured profilesnave to be just translated to get the true profiles. The TC probes proved to -quot;'be satisfactory for the intended measurel1!ents.

Item Type: Monograph (Technical Report)
Uncontrolled Keywords: Temperature measurements;Error analysis;Thermocouple;13; Radiation correction;Phase change
Subjects: ASTRONAUTICS > Astronautics (General)
Depositing User: Users 10 not found.
Date Deposited: 23 Jun 2006
Last Modified: 24 May 2010 04:14
URI: http://nal-ir.nal.res.in/id/eprint/1922

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