Effect of Nozzle Junction and Equipment Stiffness on Absorption of Pipe Thermal Loads

Abstract

As an industry norm, the nozzle local loads are considered to be local and are not considered in foundation design. Presently, this norm is under debate. One opinion is some percent of these loads are to be considered to be transferred to the foundation. The horizontal forces on the foundation are more critical than vertical forces. Attempt has been made to understand the system and create a model which will represent the system to a good approximation. A mathematical model is developed to demonstrate the actual system. It is a stiffness system consisting of equipment, nozzle junction, and connected piping. The connected pipes are heated sequentially to generate nozzle loads in axial and out plane directions. Steadystate thermal loads are calculated for the given system stiffness. Governing parameters are identified and altered to note the effect. The governing parameters identified are equipment diameter (D), nozzle location on equipment (x), and nozzle diameter (d). The effect is studied for pressure range (20–120 bar) and temperature (100–400 آ°C). The results of percentage loads transferred with respect to the governing parameters are plotted. It is observed that nozzle loads in axial directions are transferred to the foundation almost 100%, whereas out plane loads are absorbed by the system to a greater extent. Further study is required to investigate combined effects of all such nozzle loads for single equipment. The results may be refined for different materials and effect of nozzle reinforcement.