Characteristic Research Of The Pressure-exergy Transfer In Pipe-conveying System

Basing on the first and the second law of thermodynamics, this paper reviewed the developing process of the exergy's concept with non-equilibrium thermodynamics. Through a systematic study on the exergy's analytical method and exergy transfer, the characteristics of pressure-exergy transfer in the adiabatic flow were studied also. By simplifying the process of the adiabatic flow, the corresponding physical model was established and the mathematical model based on the theory of exergy transfer was built. Neglected the radiation lost of pipe and temperature variation in pipe axis line. the pressure-exergy's transmission coefficient of fully developed flow in the pipe line was derived under the assumption. Taken a section of the straight pipe which is from the power plant's main steam pipe as the thermal system, with the actual operating and structural parameters, under the premise of obtaining the average pressure's distribution of the axial cross section by Bernoulli's equation and the relevant experience formula, the pressure-exergy's transfer cofficient of the thermal system ,the distribution of the pressure-exergy's transfer cofficient along the pipe's axial direction and the distribution of the pressure-exergy flow's density were got. An objective understanding of the distribution of the pipe's exergy was obtained. The means of improve the pressure-exergy's transfer coefficients was proposed. While taking advantage of the exergy's analytical method, the thermal system's use energy was analyzed. Compared the exergy's analytical method and exergy transfer, the efficient of the pressure-exergy's transfer which were got through the both methods were nearly same. In the end of the paper, the optimization method was raised by means of revealing how to impact the actual process by the irreversible factors during energy use and the driving force how to effect the exergy transfer and transformation in the actual process, all of this were of great significient to the practical engineering...