A lot of research work has been published on the effects of sound on thermal processes in gases. Ranque and Hartmann-Sprenger temperature effects (accompanied with laud sound) have also been attributed to these effects. Lack of sufficient information as well as understanding has made them attributed to a series of physical paradoxes.
Dr. Yan Beliavsky an executive director of company Super Fine in Israel proposed the concept of Pressure Gradient Elastic Waves. Pressure Gradient Elastic Wave ( Beliavsky’s Wave) is a special elastic wave produced in compressible fluids with a pressure gradient and initial density fluctuations. These waves portray a unique property; they transfer heat from low pressure regions to high pressure regions. The observed heat transfer is independent on temperature gradient. This paper presents the outcomes of the experiment done by the author on a short vortex chamber as well as Sprenger heat tubes. This work is published in peer-reviewed journal, International Journal of Heat and Mass Transfer.
Recent research work indicates temperature separation in a short vortex chamber. Air was pumped into the vortex chamber tangentially through the nozzles. A powerful air flow was moved from the periphery to the center of the chamber. Different diaphragm diameters were adopted for the experiment. The author observed that maximum temperature separation occurred where the diameter was 30mm.
In the maximum separation mode, periphery temperature reached +465 °C and -45 °C at the center. The author increased pressure to 7 bar in 0.5 bar increments and observed the highest temperature at 7 bar.
It was shown that shock waves were not responsible for the heating. Shock waves were absent in the vortex chamber and vortex tubes (Ranque effect) and did not reach the bottom of the cavities (Hartmann-Sprenger effect). Heating and cooling maximal temperatures were computed as a result of thermodynamic transformations of the compressed gas. It is shown that measured values of heating and cooling maximal temperatures exceeded the computed values. Also the experimental results are accumulated, which in principle cannot be explained without the involving the concept of Beliavsky’s Wave.
PGEWs transfers heat from low pressure regions to high pressure regions. In the vortex tubes (Ranque effect) and vortex chambers the pressure gradient was created by rotation with the minimum pressure zone at the center and maximum at the periphery. Heat was transferred from the central part to the peripheral side wall.In the Hartmann-Sprenger tubes the low pressure is in the region of maximum velocity of the jet. Maximum pressure region is located near the plugged end of the cavity, were maximal temperatures were measured. Heat transfer intensity by Pressure Gradient Elastic Wave was determined using the pressure gradient magnitude, frequency and amplitude of initial sound fluctuations, geometry of working volume and gas attributes. The rate of heat transfer, as well as heat removal affected the value of the observed temperature
The proposed approach of Beliavsky’s Wave described sufficiently all the obtained results. These waves appear in gases under pressure gradient with presents of sound density fluetuations.
Yan Beliavsky. Experimental arguments in favor of heat transfer in compressible fluids by Pressure Gradient Elastic Waves. International Journal of Heat and Mass Transfer, volume 107 (2017), pages 723–728.
P.G.W 2014 Ltd., Israel.Go To International Journal of Heat and Mass Transfer