Direct contact condensation (DCC) has achieved a well-known significance because of exceptional reasons such as efficient heat and mass transfer characteristics. The current experimental investigation involves considering the steam cavity shape characteristics with varying steam pressure, when the saturated steam is condensed into the one-phase water atmosphere using a converging-diverging (CD) nozzle. The results indicate the four different shapes of steam jet (oscillatory, conical, ellipsoidal and double expansion–contraction). It is observed that the penetration length and the maximum expansion ratio increase with the increase in steam saturated pressure and are found in the range of 1.8–2.8 and 1–1.13, respectively. Furthermore, the current results for jet length are compared with previously developed jet length predicting models which are found to be in good agreement.

The phenomenon of direct contact condensation (DCC) has an advantageous feature of high heat, mass, and momentum transfer efficiencies and hence is highly significant for various steam-related industries such as chemical and nuclear industries. The present work investigates the underlying physics of steam plume shapes during steam–water DCC of saturated steam injection into a subcooled water-filled restricted geometry. These experiments have been performed using an orifice-type nozzle for saturated steam injection into a circular, horizontal pipe. To study the effects of pressure and the degree of subcooling of water on the steam plumes, the performed study utilized initial steam pressure and water temperature in the ranges of 1–2 bars and 60–70 °C, respectively. Numerous plume shapes such as conical, elliptical, and divergent are observed under different experimental conditions, which elongate and extend at higher subcooling temperatures. The temperature distribution within the test section as a result of steam injection has also been studied. The condensation-induced water hammer (CIWH) has also been observed under various conditions in terms of a propagating pressure oscillation.

Direct-contact condensation (DCC) has acquired an important role in the industrial sector due to its high mass and heat transfer rates. In this paper, the influence of steam pressure and water temperature on cavity shapes were studied from symmetrical and diagonal plane views. The cavity shapes observed were oscillatory, conical, ellipsoidal, and double expansion–contraction. The recompression shock wave at nozzle corners was found to cause steam cavity compression in the diagonal plane. The dimensionless penetration length was found to increase with the rise in steam pressure and water temperature and lay in the range from 3.38 to 5.55. The experimental data of dimensionless penetration length was in good agreement with previous correlations.

The steam–water direct contact condensation (DCC) process is commonly observed in various industries due to its fast heat and mass exchange characteristics. This study investigates steam plume characteristics by experimentally condensing the steam jet issuing from a swirled flow spray nozzle into stagnant subcooled water. On the basis of high-speed imaging, the effects of subcooled water temperatures on the cavity shape, its length, and maximum expansion ratio were explored. The existence of three distinct cavity shapes (ellipsoidal, double expansion–contraction and divergent) were identified. The dimensionless steam cavity penetration length and maximum expansion ratio were found to be in the range of 6.28–11.5 and 1.71–3.06, respectively. The results indicate that with the rise in water temperature, plume length and maximum expansion ratio increase.