[en] Highlights: • An ejector-assisted loop heat pipe with a flat evaporator (ELHP) is proposed. • The ejector is used to remove the generated vapor in the CC due to the heat leak. • Performances of the ELHP and basic loop heat pipe (BLHP) are compared. • Comparisons show that operating temperature of the ELHP is lower than that of the BLHP. • Compared with the BLHP, the condenser length of ELHP can be decreased significantly. - Abstract: This paper proposes an ejector-assisted copper–water loop heat pipe with a flat evaporator (ELHP) for applications in electronic cooling. In the ELHP, the ejector is used to remove the generated vapor in the compensation chamber due to heat leaks through the wick, which could eliminate the need for the subcooling liquid supplied to the compensation chamber and improve the loop heat pipe performances. The steady-state performance of ELHP is simulated based on an established mathematical model and compared with the basic loop heat pipe with a flat evaporator (BLHP). The simulation results show that the operating temperature of the ELHP can be lower than that of the BLHP under the same heat load condition. Since the working fluid subcooling zone in the ELHP condenser is not required, the total length of the pipe-in-pipe type condenser also can be decreased by 24.4–34.8% when compared with that of the BLHP under given operating conditions. In addition, the effects of the thickness of the wick, the total length of the condenser, the inner diameter of the vapor line and the mass flow rate and inlet temperature of the cooling water on the performances of the ELHP are also evaluated in this study. These simulation results indicate that the ELHP can achieve a better performance than BLHP, which could be beneficial to the applications in electronic cooling.