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...

Examples

Embodiment Construction

[0071] 1. Divide circuits and pipe sections:

[0072] Circuit division: The geometric structure and heat absorption of the tubes that make up the water wall of the boiler are different, and there are structural deviations and thermal deviations. Adjacent tubes with basically the same geometric structure and heat absorption deviation are divided into the same circuit, and the thermal parameters and geometric structures of each single tube are considered to be exactly the same. At the same time, in the part where the heat absorption deviation changes significantly in the horizontal direction of the furnace or the geometric structure changes greatly, the circuit division should be dense, and the number of distribution pipes corresponding to each circuit is small, while in the area where the heat absorption deviation or geometric structure changes gently, the circuit division should be It can be relatively sparse, and the number of pipes corresponding to each circuit is relatively...

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...

Examples

Embodiment Construction

[0071] 1. Divide circuits and pipe sections:

[0072] Circuit division: The geometric structure and heat absorption of the tubes that make up the water wall of the boiler are different, and there are structural deviations and thermal deviations. Adjacent tubes with basically the same geometric structure and heat absorption deviation are divided into the same circuit, and the thermal parameters and geometric structures of each single tube are considered to be exactly the same. At the same time, in the part where the heat absorption deviation changes significantly in the horizontal direction of the furnace or the geometric structure changes greatly, the circuit division should be dense, and the number of distribution pipes corresponding to each circuit is small, while in the area where the heat absorption deviation or geometric structure changes gently, the circuit division should be It can be relatively sparse, and the number of pipes corresponding to each circuit is relatively...

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