Modeling and Flow Analysis of Self-Propulsion Nozzle for Debris Removal
Abstract
Nozzles are essentially a system of varying cross section that directs or modifies the fluid flow, typically increasing the velocity of the fluid at the expense of its pressure energy, on leaving a system of a pipe or a tube. Two classes of commercial nozzles, pressure washer and sewer nozzles, are used widely for various applications. Typical pressure washer operates between 2.5 and 4 gpm whereas sewer nozzles operate from 4 gpm till 25 gpm. Both classes of nozzles have always been studied independently but through this research, am attempt was made to bridge the gap between the 2 classes of nozzles wherein modified pressure washer nozzle can act as a substitute for sewer nozzles.
Nozzle parameters like jet diameter, upstream- downstream pressure condition, number of jets and turbulence model have been thoroughly studied for C-D nozzle and it is observed through the simulation results that the flow rate and force increase as a square of the jet diameter and flow rate increases linearly with increase in multi-orifice jets.
High net forces and low impact forces cause damage to the nozzle as ideally the rate of penetration should equal the rate of cutting (nozzle moving at a constant velocity). Due to variations in drag forces and material removal rate, a positive net self-propulsion force is required for effective working of the nozzle. The optimal nozzle configuration obtained from analysis has 3 forward jets each 0.04” diameter and 8 reverse jets each 0.05” diameter.
The performance of the optimal nozzle is 9 times higher than the base spray washer nozzle which was modified. The flow rate achieved is 25.83 gpm (increased from 2.85 gpm), a 9-fold increase in flow rate, making the pressure washer nozzle work as a sewer nozzle which typically have a flow rate of 20 gpm. The impact force of nozzle is 14 lbf for debris removal (increased from 6.5 lbf). The net self-propulsion force is 12 lbf.
Citation
Srinivasan, Srivignesh (2020). Modeling and Flow Analysis of Self-Propulsion Nozzle for Debris Removal. Master's thesis, Texas A&M University. Available electronically from https : / /hdl .handle .net /1969 .1 /200811.