Experimental study of thermal-hydraulic efficiency of a in-line tube bundle with reciprocating flow pulsations

Pulsating flows can occur spontaneously or be created artificially to heat transfer enhancement. Reciprocating flow pulsations can significantly enhance heat transfer. However with heat transfer increasing, energy costs also increase. There are very few existing studies assessing the energy efficiency of tube bundles with forced flow pulsations. Therefore, in this paper, the thermal-hydraulic efficiency of an in-line tube bundle is studied with flow pulsations. The experimental study was carried out at a Reynolds number of 3000 and a Prandtl number of 4. Flow pulsations had a reciprocating symmetrical and asymmetrical character. Flow pulsations were created using a hydraulic cylinder and a controlled pneumatic system. During the experiments, the influence of the pulsation parameters on the power consumption of the pneumatic system compressor and pumping equipment is determined. The thermal-hydraulic efficiency of a tube bundle is determined at the same Reynolds numbers and the same powers at the pulsating and steady flow. It is established that the thermal-hydraulic efficiency at the same Reynolds numbers decreases with increasing pulsation intensity, while the thermal-hydraulic efficiency at the same powers increases. It is found that the thermal-hydraulic efficiency of a tube bundle is higher at asymmetric flow pulsations. For asymmetric pulsations, a thermal-hydraulic efficiency close to unity is obtained. The thermal-hydraulic efficiency of a tube bundle at flow pulsations can be increased by increasing the efficiency of the pulsation-generating system.