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Abstract Channels packed with disordered particles are of great importantance for enhancing heat transfer. This paper builds the convective heat transfer experiment platform and studies the heat transfer coefficient in a channel packed with disordered cement particles experimentally. Under the given heat sources, cooling the channel with air at steady state obtains the data, which calculates the convective heat transfer coefficient. Then fitting the Nusselt and Reynolds numbers offers the experimental correlation. Error analysis and comparison with the existing correlations validate the fitted correlation. Discussion on the Nusselt number and wall temperature shows that the Nusselt number in the packed channel is approximately eight times than that in the smooth channel, which provides an effective method for intensifying the effect of channel wall cooling. Moreover, the inner wall temperature of channel with smaller particles is lower, which means the heat transfer enhancement performs better. [ABSTRACT FROM AUTHOR]

• Constructing an experimental platform of a packed channel with disordered cement granules. • Fitting the data of Nusselt and Reynolds numbers provides an experimental correlation. • A mathematical model of the channel packed with granules is proposed. • Using the inverse problem method determines the average local velocity of cooling air. The channels packed with disordered granules are common in industry, which permits an improved performance of the facility as well as the energy efficiency. This paper describes the construction of an experimental platform of a packed channel with disordered cement granules. Using the method of dimensionless number correlation, fitting the data of Nusselt and Reynolds numbers provides an experimental correlation. Analysis shows that the Nusselt number in a packed channel is approximately eight times that in a smooth channel. The inner-wall temperature of a channel with smaller granules is lower, implying the heat transfer is stronger. The inverse problem method is adopted to measure the local average velocity and obtain the temperature distribution, permitting then a determination of the Reynold number based on the local average velocity in the channel combined with the fitted experimental correlation and a mathematical model of the experimental section. Comparisons with the Reynold number obtained from the superficial flow velocity shows that the Reynold number obtained from the average local velocity is much smaller and in particular, for the same mass flow rates, the latter Reynold number of the channel packed with smaller granules is larger than that packed with larger granules. It provides useful tools to analysis the local heat transfer performance to improve the energy efficiency in actual applications. [ABSTRACT FROM AUTHOR]