Boiler Tube Re-search (Re-Heater) Part 7

Please visit Boiler Tube Research Part 6 for previews explanation.


Simulation Supporters

So as to support the result analysis of the formerly who stated that leakage re-heater 3 caused with a depletion of the outer wall of it can no longer hold internal pressure great, then these simulations will be focused to analyze voltage is produced as a result of depletion of the walls of a pipe.

Table 3.14 presenting some cases the simulation pipe thickness that experienced depletion and 60 %.Based on operating conditions, to the areas re-heater pipe in the boiler of a, the displacement of heat convection is a method of the most dominant .Because of that, on these simulations to thermal analysis the boundary conditions convection will be included to obtain it to be accurate.





Pertaining to failure at the pipe 4 , focused on to computer simulation 1 the knowing the distribution of temperature that happened on the wall due to the thermal gradient 2 the analyzes the distribution of voltage and deformation that happened resulting from contact with foreign matter. The main purpose is verify whether at the time of the collision happened, deformation plastic the pipe happens when forming cold or hot forming. In the simulation this, foreign matter modeled with a triangular form as misshapen forms that occurred at the pipe 4.

Data input simulation of materials, and the boundary conditions used to use a computer simulator re-heater in the pipe 3 and pipe 4 show on table 3.2. and 3.3. The simulation result as picture 3.39 showing the distribution von mises depletion of the maximum of 20 %. It is obtained from the conclusion that when the pipeline had depletion 20 % just ( or thick pipe 80 % x W ) the maximum tension von mises has reached the limit melt material that is required. As seen in the picture is 3.39 tension remains excessive stress ( mostly ) began to appear on the wall along the pipeline.This may result in the occurrence of deforming plastic along the surface of the inner ( see picture 3.40 ).



The presumption that is because of leakage on pipe 3 more internal pressure from the steam ( and thick the walls of condition where there has not been able to hold the size of this pressure ) reinforced with the results of the simulation pertaining to a vector voltage principal occurring on a pipe with a thick 80 percent of the w or thinning of 20 percent ( see a picture 3:41). Can be seen that emerged from the surface of the voltage principal pipe in part. This indicates that internal pressure of fluid is the dominant factor tore the cause of the wall of a pipe 3.

The value is in line with the lack of the wall of large pipes. Also can be seen Of that direction of a voltage principal the results of the simulation ( figure 3.41 b ) have the same direction with the direction of torn a pipe found (figure 3.41 c ). In this way we can conclude that the interaction of the influence of internal pressure pipe as well as thermal gradient on the wall a pipe who have started thinning due to erosion shoot blower this is what causes the torn on a pipe 3. The results of this is in accordance with the results of the analysis before.





Continue to Boiler Tube (Re-Heater) Research Part 8 Final.