The mathematical control model for dynamic start-up process of the VTE-MED seawater desalination system was establishedemploying the previous developed non-linear differential equations for system design and performance analysis. The influences on thestart-up process of the operating parameters, such as the initial feed brine flow rate and the top brine temperature were analyzed.The relationships among the feed brine flow rate, the gained output ratio (GOR) and the start-up time were also investigated, whichcan be evidence to determine the optimal initial feed brine flow rate. The results also indicate that the system can consume the total heatrating generated by the low temperature nuclear heating reactor (LT-NHR) even at the most initial start-up stage, implying the presentdesalination system has excellent coupling characteristics with the LT-NHR. With necessary experiments verifications, the start-up controlmodel developed in this paper can be the theoretical base for the analysis of dynamic performances of the seawater desalinationsystem.

The correlating factors for-ow condensation in small/mini-diameter tubes are analyzed by energy consideration. Based on the in-situ interface con®guration, an analytical model is proposed for predicting the heat transfer characteristics. Both analytical and experimental results show that gravity has a decreasing e.ect on-ow condensation in small/mini tubes. The inclination angle a.ects condensation heat transfer mainly by distributing gravity in stratifying the-uids and thinning the liquid ®lm. In larger tubes, the former may become the main reason for heat transfer enhancement, especially in high vapor quality zone and at low inlet vapor Reynolds number. Comparison with the experimental data indicates that the proposed analytical model has a good capability for predicting-ow condensation heat transfer in small/mini-diameter tubes. # 2000 Elsevier Science Ltd. All rights reserved.

In order to understand the performance of a large-capacity VTE-MED nuclear seawater desalination systemthoroughly, the responding characteristics of the system to the off-design operating conditions were studied. Theinfluence of scale deposit in tubes on the heat transfer areas needed and on the heat transfer coefficients with high topboiling temperature (TBT) was illustrated. The decrease of GOR, and also the damage to the normal operation of thesystem caused by temperature drop of feed brine because of seasonal variation, were explored, based on which acorresponding approach for adjusting feed brine flow rate was proposed. An optimal brine feed flow rate was alsoproposed to obtain the highest GOR under different heat loadings. The work could be helpful for the efficient and safeoperation of nuclear VTE-MED desalination plants.

A physical and mathematical model for the multi-effect distillation process with vertical tube evaporators(VTE-MED) coupled with a nuclear heating reactor (NHR) was described. Results of analysis on thermal hydraulicperformances of the NHR-VTE-MED system are provided. Two types of temperature difference distribution schemes(equal temperature difference and in-section equal heat transfer area) were adopted for the thermal hydraulic performanceanalysis. Heat transfer coefficient, heat transfer area, and production of potable water in every effect were analyzed. Theanalysis shows that the GOR in the NHR-V1T.-MED system for the two types of temperature difference dislributionschemes studied can reach 20.

An analytical model, simultaneously accounting for gravity, vapor shear along axial direction and surface tension e.ects on the condensate ®lm layer, is proposed for fow condensation process in horizontal annulus with small/mini diameter inner tube and traditional industrial-used outer adiabatic tube. The analysis shows that, the e.ect of surface tension can not be neglected for small/mini tube of diameter less than 3 mm o.d., especially in low vapor quality zone. The shear stress and surface tension infuence the fow condensation mainly by means of distributing condensate ®lm uniformly along tube circumference in horizontal annulus. Experiments were conducted to examine the analysis. # 2000 Elsevier Science Ltd. All rights reserved.

The Kelvin-Helmholtz instability of phase-change interface during flow film condensation in vertical mini-diameter tube was studied here by means of energy analysis. According to the interfacial boundary conditions, the film thinning effect and the phase-change area enlarging effect by interfacial waves on heat transfer enhancement were analyzed for flow condensation in tubes with different diameter. It is indicated that, in mini-diameter tube, more obvious heat transfer enhancement due to interfacial waves can be expected than that in normal-sized tube, and the interfacial waves enhance the heat transfer mainly by film thinning effect.-2003 Elsevier Science Ltd. All rights reserved.

A physical and mathematical model for the multi-effect distillation process with vertical tube evaporators (VTE-MED) coupled with a nuclear heating reactor (NHR) was described. Results of analysis on thermal hydraulic performances of the NHR-VTE-MED system are provided. Two types of temperature difference distribution schemes (equal temperature difference and in-section equal heat transfer area) were adopted for the thermal hydraulic performance analysis. Heat transfer coefficient, heat transfer area, and production of potable water in every effect were analyzed. The analysis shows that the GOR in the NHR-V1T_.-MED system for the two types of temperature difference dislribution schemes studied can reach 20.

The Kelvin-Helmholtz instability of evaporating thin falling film flow in vertical tube is studied by method of energy analysis. Based on the rules that the interfacial capillary waves come from the balance of works done by inertial force, surface tension on phase-change interface, and also capillary force on tube wall, the stability behaviors of falling film with different Reynolds number and different perturbation wavelength are explored in detail. The analysis indicates that the main reason of film breakup by increasing tube wall heat flux is that, the stability effect of capillary adsorbability on tube wall is weakened as surface tension waving is enhanced by improving tube wall temperature.

order to investigate the optimization of the design parameters of the VTE-MED system coupled with NHR-200 [1], effects of system design parameters (including system effect number, material &heat transfer tube, geometric size of heat transfer tube, feed seawater temperature and top brine temperature) on performance of the VTE-MED system were analyzed by using the developed code [2]. Results of the analysis are presented in this paper.

In this paper we report on a theoretical analysis of film condensation heat transfer in a vertical micro tube with a thin metal wire welded on its inner surface. Both the radial and the axial distributions of condensate liquid along the tube wall and over the meniscus zone, formed by the wire in contact with the tube inner surface, are determined based on the minimum energy principle over the liquid–vapor two-phase flow system. The influences of the contact angle between the condensate liquid and the channel wall as well as the wire diameter on the condensate distributions and the heat transfer characteristics are examined. It is found that an increase in the wire diameter results in significant enhancement of heat transfer in the channel. It is also demonstrated that the wettability between the wire and the condensate has a little influence on the overall heat transfer coefficients, although it affects the condensate liquid distribution. Compared to a round tube with the same inside diameter, significant enhancement of condensation heat transfer is found for the present configured microchannel.