Heating effects on swallowing under the influence of dilating peristaltic waves

Abstract

A mathematical model of heating effects during swallowing of a single bolus in an oesophagus is presented analytically. The inferred results may be useful in analyzing the role of heat in cryosurgical treatment of oesophagus in which cooling of cancerous tissues is a methodology for treatment. Heating effects on the axisymmetric flow of a Newtonian fluid are studied in a finite length tube to model swallowing in oesophagus. The long wavelength and low Reynolds number approximations are employed for solution. This further neutralizes curvature effects. Besides, peristaltic waves are considered to contract and relax within the natural boundary but progressively dilate in amplitude, which is a requirement for naturally increasing pressure in the distal oesophagus. The main observation is that pressure drops when either the Grashof number or the heat source/sink parameter increases along the oesophageal axis. Axial velocity of the fluid increases with Grashof number as well as heat source/sink parameter. It is further observed that the pressure required for swallowing is less when heat propagates in the oesophagus. Heat propagation also reduces the region of reflux. Hence this indicates an easy swallowing anything that is warm with reduced reflux region. However, it is evident that since tissues are cooled during cryosurgery, swallowing will be badly retarded with an enhanced region of reflux. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2024.