Experimental research on in-tube condensation under steady-state and transient conditions

Tanrikut, A
Yesin, O
In this research study, in-tube condensation in the presence of air was investigated experimentally at a heat exchanger of countercurrent type for different operating conditions. The test matrix for the steady-state condition covers the range of pressures P = 1.8 to 5.5 bars, vapor Reynolds numbers Re, = 45 000 to 94 000, and inlet air mass fraction values Xi = 0 to 52%. The effect of air manifests itself by a reduction in the local heat flux and the local heat transfer coefficient. The local heat transfer coefficient is inversely proportional to the local air mass fraction. Both the local heat flux and the heat transfer coefficient vary with the system pressure and vapor mass flow rate. There is no effect of inlet superheating on the local heat flux. The film Reynolds number lies in the range of the turbulent region. Two experiments simulating loss of coolant to the secondary side of the condenser were performed, for pure steam and for an air/steam mixture. These transients show that the vapor suction rate, effective condensation length, and overall heat transfer rate are a function of the coolant boiloff rate and the air mass fraction.


Adsorption calorimetry in supported catalyst characterization : adsorption structure sensitivity on pt(y-Al2o3
Üner, Murat; Üner, Deniz; Department of Chemical Engineering (2004)
In this study, the structure sensitivity of hydrogen, oxygen and carbon monoxide adsorption was investigated by changing the metal particle size of Pt/Al2O3 catalysts. 2 % Pt/Al2O3 catalysts were prepared by incipient wetness method; the particle size of the catalysts was manipulated by calcining at different temperatures. The dispersion values for the catalysts calcined in air at 683K, 773K and 823K were measured as 0.62, 0.20 and 0.03 respectively. The differential heats of adsorption of hydrogen, carbon ...
Estimation of the formation temperature from the inlet and outlet mud temperatures while drilling geothermal formations
Tekin, Sema; Akın, Serhat; Department of Petroleum and Natural Gas Engineering (2010)
Formation temperature is an important parameter in geothermal drilling since it affects all the components of the system such as drilling fluid, drilling operations and equipment through mud temperatures. The main objective of this study is to estimate the formation temperatures of five geothermal wells in Germencik-Ömerbeyli geothermal field by using inlet and outlet mud temperatures obtained during drilling. For this purpose, GTEMP, a wellbore thermal simulation model is used to simulate the process of dr...
Polyimide and PEBAX flat and hollow fiber membranes for gas separation
Özdemir, Nur Konçüy; Kalıpçılar, Halil; Department of Chemical Engineering (2017)
This thesis analyzes the effect of polyimide (PI) hollow fiber membrane spinning conditions including dope solution flow rate, bore liquid flow rate, addition of more volatile solvent to dope solution, air gap height and heating zone temperature on the ideal gas separation performance and membrane morphology. The effect of PEBAX1657 coating of PI hollow fiber membrane was also investigated. The effect of incorporation of ZIF-8 crystals to PEBAX1657 flat sheet membrane, the effect of coagulant type for the p...
Oxidation of Si surface by a pulsed Nd : YAG laser
Aygun, G; Atanassova, E; Alacakir, A; Ozyuzer, L; Turan, Raşit (2004-06-07)
SiO2 thin films have been obtained by 1064 nm Nd:YAG laser oxidation of p-Si in the presence of O-2. The thickness uniformity, dielectric and electrical properties of the layers have been studied. The effect of both the laser beam energy density and the substrate temperature on the oxide growth is also discussed. It was established that there exists an interval of laser beam energy density in which the oxidation occurs without surface melting. The oxidation process is controlled by the laser beam energy den...
Reaction kinetics of calcium chloride - ammonia reactive system and theoretical simulation of heat and mass transfer in porous slab pellets
Karakaş Helvacı, Zeynep; Uludağ, Yusuf; Karakaş, Gürkan; Department of Chemical Engineering (2023-1-24)
The reactive systems between ammoniated CaCl2 and NH3 were investigated in terms of heat and mass transport phenomena coupled with reaction kinetics. The reversible reaction rate based on the Langmuir-Hinshelwood model was suggested to express the net reaction rate, including both the adsorption and desorption terms. Experiments at three temperatures were conducted to evaluate the kinetic parameters, pre-exponential factors, and activation energies. The parameters were evaluated by Non-Linear Regression (NL...
Citation Formats
A. Tanrikut and O. Yesin, “Experimental research on in-tube condensation under steady-state and transient conditions,” NUCLEAR TECHNOLOGY, pp. 88–100, 2005, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/65710.