Solid-particle erosion in the tube end of the tube sheet of a shell-and-tube heat exchanger

Abstract

SUMMARYErosion is one of the major problems in many industrial processes, and in particular, in heat exchangers. The e ects of ow velocity and sand particle size on the rate of erosion in a typical shell-and-tube heat exchanger were investigated numerically using the Lagrangian particle-tracking method. Erosion and penetration rates were obtained for sand particles of diameters ranging from 10 to 500 m and for inlet ow velocities ranging from 0.197 to 2:95 m=s. A ow visualization experiment was conducted with the objective of verifying the accuracy of the continuous phase calculation procedure. Comparison with available experimental data of penetration rates was also conducted. These comparisons resulted in a good agreement. The results show that the location and number of eroded tubes depend mainly on the particle size and velocity magnitude at the header inlet. The rate of erosion depends exponentially on the velocity. The particle size shows negligible e ect on the erosion rate at high velocity values and the large-size particles show less erosion rates compared to the small-size particles at low values of inlet ow velocities. The results indicated that the erosion and penetration rates are insigniÿcant at the lower end of the velocity range. However, these rates were found to increase continuously with the increase of the inlet ow velocity for all particle sizes. The particle size creating the highest erosion rate was found to depend on the ow velocity range.

Performance investigation of micro- and nano-sized particle erosion in a 90° elbow using an ANFIS model

“…This rise is approximately 9.5 times at volume concentration of 4%. Increasing the volume concentration from 2% to 4% resulted in a lift in total erosion to 8 times which is similar to findings by Habib, Badr, Said, Ben-Mansour, and Al-Anizi [43]. Fig.…”

Numerical identification of critical erosion prone areas in tube heat exchangers

“…This is due to the stronger recirculating flow in one half of the plenum, associating with a cross flow from one half of the plenum to the other half and a rotational flow in the inlet entrance. The particle trajectory traces captured by a high-speed digital camera (Habib et al, 2006) showed a flow pattern with one more swirl in the right half side of the tube entrance than the left half size, which well demonstrated the flow pattern simulated in this work. The simulation of gas flow in a similar heat exchanger (Bremhorst & Brennan, 2011) showed approximately symmetrical velocity and flow angle contours at tube sheet at a much higher flow rate than the present work.…”

“…It was found that high erosion only occurs at scattered small areas. The simulations of erosion in a heat exchanges with 824 tubes (Habib et al, 2005) and in a heat exchanger with 38 tubes (Habib et al, 2006) also showed a location profile of the critical erosion tubes and the serious erosion only occurred on a few tubes. Figure 7 shows that HE1 has the most serious erosion on the tube sheet, and the maximum erosion rate of HE3 is the lowest.…”

“…Some authors (Campos-Amezcua et al, 2007;Njobuenwu & Fairweather, 2012;Parsi et al, 2014;Peng & Cao, 2016;Vieira et al, 2016;Zhang et al, 2007) surveyed the available models and examined their application in the prediction of the solid particle erosion of steam turbine components (Campos-Amezcua et al, 2007), the sand particle erosion of pipelines (Parsi et al, 2014), the solid particle erosion damage of flat specimens in water or air flow and 90°e lbows in air flow (Zhang et al, 2007), four different 90°s quare cross-section bends (Njobuenwu & Fairweather, 2012) and 90°elbows due to gas-solid flow (Peng & Cao, 2016;Pereira et al, 2014;Vieira et al, 2016). The Neilson-Gilchrist erosion equations (Neilson & Gilchrist, 1968) were used by Wallace et al (Wallace et al, 2000) and, thereafter, were used by Habib et al to model erosion in a pipe with abrupt contraction (Badr et al, 2005;Habib et al, 2007;Habib et al, 2004), in the tube entrance region and the tube end of a shell and tube heat exchanger (Habib et al, 2006;Habib et al, 2005), and in the tube entrance region of an air-cooled heat exchanger (Badr et al, 2006). Gao et al (Gao et al, 2016) investigated the characteristics of erosion caused by different size sand particles in a shell and tube heat exchanger.…”

“…Building models for the structure of tube heat exchangers is still an art to precisely simulate the multiphase flow and particle erosion in their critical regions. A symmetrical model was used to study the sand erosion of a shell and tubular heat exchanger at different water velocities and particle sizes, where k-ε turbulence model and the Lagrangian approach were used for fluid flow and tracking particles, respectively (Habib et al, 2005;Habib et al, 2006). However, the simulation of this type of heat exchangers with the Reynoldsaveraged Navier-Stokes (RANS) equations and the k-ω SST (Menter's shear stress transport) turbulence equations showed that the flow in the inlet plenum is asymmetrical (Bremhorst & Brennan, 2011).…”