Grate Bar Impingement Cooling for Stoker Incinerators
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Stoker type incinerators face inadequate cooling performance for grate bars, leading to increased temperature and reduced lifespan, especially when cooling air flow velocity cannot be increased.
Innovation Solution
A grate bar design featuring an upper wall portion, a front wall portion, and a partition wall with cooling holes that eject a cooling medium for impingement-cooling, along with a slit for air discharge, and optionally a fin for enhanced heat radiation, optimizing the distance and diameter ratio of cooling holes to improve cooling efficiency and reduce manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the flow velocity of cooling air is increased to improve cooling performance, then cooling efficiency is improved, but the system cannot increase flow velocity due to operational constraints
Solution Approach 1:
The patent changes the cooling mechanism from forced convection to impingement cooling by introducing cooling holes in the partition wall. This parameter change allows effective cooling without increasing air flow velocity, as the cooling medium is directed directly onto the grate bar surface through the cooling holes, achieving high cooling efficiency at lower flow velocities.
2Reliability
If cooling performance is insufficient, then the grate bar temperature increases, but increasing cooling performance requires increasing flow velocity which is not possible
Solution Approach 1:
The patent introduces cooling holes in the partition wall to change the cooling parameter from flow velocity-dependent forced convection to impingement cooling. This allows the system to achieve sufficient cooling performance and extend grate bar lifespan without increasing air flow velocity, directly addressing the reliability issue.
3Temperature
If cooling holes are made larger or more numerous to improve cooling, then cooling performance improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent optimizes the cooling hole parameters (inner diameter Di and distance L) to achieve effective cooling within reasonable manufacturing tolerances. By carefully selecting the ratio and dimensions of cooling holes, the design achieves sufficient cooling performance without requiring extremely tight manufacturing precision, thus resolving the contradiction between cooling efficiency and manufacturability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design enhances cooling performance by direct impingement of the cooling medium on the grate bar surfaces, reduces pressure loss, and extends the lifespan of the grate bar while simplifying the structure for easier maintenance.
Implementation Method 1
a plurality of cooling holes which are formed in the partition wall main body and which are configured to eject a cooling medium toward a back surface of the upper wall portion to cool the upper wall portion by impingement-cooling
Implementation Method 2
the cooling air flows along a wall of the grate bar which is a cooling target, and heat is transported through diffusion of vortices generated near the wall
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A grate bar (1) includes an upper wall portion (2) which extends in a first direction (D), a front wall portion (3) which extends downward from a distal end of the upper wall portion (2), a channel (S) which is provided on a back side of the upper wall portion (2), and a partition wall (8) which vertically divides the channel (S) and includes a partition wall main body (9) of which a main surface faces the upper wall portion (2) and a plurality of cooling holes (10) which are formed in the partition wall main body (9) and eject a cooling medium toward a back surface of the upper wall portion (2) to cool the upper wall portion (2) by impingement.