In this study, the effects of rotating straight and helical inner tubes is experimentally discussed to determine heat transfer and pressure losses in rotating tubes and improve heat transfer. The outer tube remains stationary and the inner tube is rotated at different speeds in the work. In the experiments for straight and helical tubes, the flow regime is turbulent. According to the results, Nusselt number, pressure loss, efficiency of heat exchanger were gauged. In addition, empirical formulas were obtained for each pipe type. It is observed that as the rotation speed of the pipe increases, the heat transfer rate increases. The pipe that provides the best increase in heat transfer is the five helixes tubes. At 5 helixes tubes; after the number of revolutions per minute (rpm) exceeds 300, the increase in heat transfer rate has almost halt. At 5 helixes tubes and at 300 rpm speed ; when the flow of cold water through the annular gap with the fluid passing through the inner tube is equal, the heat transfer increases by 124.10% compared to straight tube, 23.47% compared to 2 helixes tubes, 7.92% compared to 3 helixes tubes and 1.65% compared to 4 helixes tubes. Maximum effectiveness was obtained while rotating with 300 rpm in 5 helixes pipes.

In smoke pipe boilers, the thermal efficiency of the boiler depends on the smoke pipe diameter, smoke pipe length and the heat transfer between the smoke pipe and the outlet chimney. If the heat in the smoke pipes is effectively transported through the pipes, the heat distribution on the surfaces is balanced and the thermal efficiency of the boiler increases. In this study, the improvement of heat transfer in a solid fuel boiler with 125,000 kcal / h heat capacity with a diameter of 42 mm, chimney diameter of 230 mm and water inlet and outlet diameters of 65 mm was investigated by using 4 different types of strip turbulators. Experiments were carried out with turbulators placed in all the smoke pipes in the boiler. Firstly, experiments were carried out without placing a turbulator inside. In the second step, by placing turbulators in the smoke pipes, experiments were made for each type and heat transfer was calculated. In the experiments, the flow rate of the fan was changed with the help of damper and the reynolds number was calculated between 18000 and 28000. Turbulator experiments for heat transfer improvement have increased by at least %15 and at most %41 compared to turbulator free experiments. For the heat transfer increase values obtained because of calculations, predictive models were obtained using machine learning algorithms SVM (support vector machine) and decision tree (M5P model tree). The resulting models have been analyzed for error analysis and have been shown to successfully predict heat transfer increase values.

Bu çalışmada, duman borularının çapı 42 mm, baca çapı 230 mm ve su giriş ve çıkış çapları 65 mm olan 125.000 kcal/h ısı kapasiteli katı yakıtlı kazanda, 4 farklı tipte şerit türbülatör kullanılarak ısı transferinin iyileştirilmesi incelenmiştir. Kazandaki duman borularının tümüne yerleştirilen türbülatörlerle deneyler yapılmıştır. İlk olarak içerisine türbülatör yerleştirmeden deneyler yapılmıştır. İkinci adımda ise duman boruları içerisine türbülatörler yerleştirerek her tip için ayrı ayrı deneyler yapılmış ve ısı transferi hesaplanmıştır. Deneylerde fan debisi damper yardımıyla değiştirilerek Reynolds sayısı 1800 ile 2800 arasındaki değerlerde hesaplamalar yapılmıştır. Isı transferi iyileştirmesi için yapılan türbülatörlü deneyler, türbülatörsüz deneylere göre ısı transferinde en az % 44, en fazla % 82 oranında artış sağlanmıştır. Hesaplamalar sonucu elde edilen basınç farkı değerleri için yapay sinir ağı (YSA) kullanılarak tahminsel bir model elde edilmiştir. Elde edilen modelin hata analizleri yapılmış ve basınç değerlerini başarılı bir şekilde tahmin ettiği gösterilmiştir.