Abstract: The flow-field and shock wave behavior in thermal vapor compressor(TVC),a popular equipment in wastewater recycling industry,was empirically approximated,mathematically formulated with standard k-ε model and numerically simulated with Fluent software.The influence of the TVC operating conditions on the flow-state and properties of shock-wave was investigated.The simulated results show that the operation steam experiences: i) the rapid velocity-increase and pressure-decrease in the ejector,ii) slow velocity-decrease and pressure-increase,accompanied by reflux,in the mixing-section,iii) fast velocity-decrease in the expansion-section; and that the formation of rhombic shock wave significantly depends on the high-pressure of the active operation steam and on the low-pressure of the passively sucked up steam.We suggest that the simulated results be of some technological interest in design optimization of thermal vapor compressors.