Numerical and experimental study to examine methods to increase the convectional heat transfer of recuperator tubes

Journal of Physics Conference Series, vol. 2685, pp. 012010

Abstract

Abstract The use of structured tubes in tube bundle recuperators is intended to improve the energy efficiency of gas-fired industrial furnace systems with central air preheating. Currently, smooth tubes as well as smooth tubes with internal twisted tape are commonly utilised. The increased surface area of structured tubes leads to an increased heat transfer between the off-gas and the combustion air. However, structuring leads to an increased pressure loss. The aim is to find an optimal operating range in which the pressure losses are still acceptable and the greatest increase of heat transfer compared to the reference will be achieved. Smooth tubes and also smooth tubes with twisted tapes are considered as reference systems in comparison to two concave structured tubes. CFD simulations were used to investigate the influence of the operating parameters of combustion air velocity and off-gas velocity on heat transfer according to industrial scale. The simulations have shown that the heat flow increases with the honeycomb depth and strongly depends on the operating conditions. Experimental measurements in a test bench were carried out to validate the model and confirm the positive influence of structuring on heat transfer.

Authors 4

1. Eileen Trampe corresponding Aachen

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University - Department for Industrial Furnaces and Heat Engineering, Kopernikusstr. 10, 52074 Aachen, GERMANY

2. Justin Hauch Aachen

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University - Department for Industrial Furnaces and Heat Engineering, Kopernikusstr. 10, 52074 Aachen, GERMANY

3. Dominik Büschgens Aachen

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University - Department for Industrial Furnaces and Heat Engineering, Kopernikusstr. 10, 52074 Aachen, GERMANY

4. Harry Pfeifer Aachen

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University - Department for Industrial Furnaces and Heat Engineering, Kopernikusstr. 10, 52074 Aachen, GERMANY