General hydrodynamic calculation method for ultra-supercritical boiler

Abstract

The invention discloses a general hydrodynamic calculation method for an ultra-supercritical boiler, and provides a flow network system method consisting of a nonlinear model applied to a computer. The calculation method is suitable for hydrodynamic calculation and wall temperature safety analysis of the ultra-supercritical once-through boiler under various boiler overall arrangement forms, various pipe coil forms, various combustion technologies and various mass velocity combinations. The method comprises the steps of simplifying a water wall into a flow network system consisting of elements such as a connecting pipe loop, a heated loop, a pressure node and the like according to structure characteristics of the water wall and heat load distribution of a furnace chamber; and building the nonlinear calculation model of flow distribution according to a mass conservation equation, a momentum conservation equation and an energy conservation equation. Through direct solving of a nonlinear equation set, flow distribution and node pressure distribution in the heated loop and a connecting pipe are determined, and based on this, boiler water wall flow and metal wall temperature are subjected to safety check, so that guidance calculation can be performed for design and safety check of the boiler.

Description

technical field [0001] The invention belongs to the field of thermal energy engineering and relates to the design and safety check of an ultra-supercritical boiler water wall system. In particular, it relates to a general design and safety check method that can be used in various forms of ultra-supercritical boiler water wall systems. Background technique [0002] The research on the hydrodynamic characteristics of ultra-supercritical boiler water wall is one of the key technologies of ultra-supercritical boiler, which is of great significance to the optimal design of water wall and the safe and reliable operation of the boiler. At present, the hydrodynamic calculation methods mainly include the chord-intersection calculation model and the polynomial fitting model. The chord-intercept method uses the chord-intercept method to solve the nonlinear momentum conservation equation, which is second-order convergent. From the mathematical point of view, because of the need to sol...

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Problems solved by technology

However, this polynomial fitting calculation model can only be calculated for simple series-parallel circuit combinations

In the complex water wall structure, it needs to be simplified, which greatly limits the scope of application of the model and also affects the accuracy of the model

[0003] In order to overcome the difficulties in hydrodynamic calculation of complex ultra-supercritical boilers, many scholars have used computers to write hydrodynamic calculation programs, but most of them are aimed at a specific ultra-supercritical boiler.

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