Abstract: Oil transportation, static cool-down process during shut-down period and restart of the crude oil pipeline can be effectively simulated in the experimental loop(EL), with which the flow behavior of a certain fluid can be studied as well.Compared with the single-pipe EL with a huge water bath, the casing EL has many advantages of small volume, water saving, ease of operation and maintenance and so on.Dynamic and static cool-down process for the casing EL are simulated by NHT method.The results show that under preset cooling rates of the water, the axial temperature difference of the oil at six-meter intervals is within 0.03 ℃, in conditions of oil and water fluxes no less than 50 mL/s and 1.0 m³/h separately.The radial temperature difference between oil and water is within 0.55℃ during dynamic cool-down process, and after cooling for 35 min, the oil and water begin to cool down with the same cooling rate.Moreover, the radial difference is within 0.12℃ during static cool-down process, and 25 min.Later, the oil and water start to cool down synchronously.