Advanced Materials Research Vols. 1070-1072

Abstract: The performances of centrifugal fans, two primary air fans and two secondary air fans were tested in BECR load and were compared with design parameters. The results show that air fan capacity excesses in practical BECR are 40% and 80%, beyond the design value. An operation optimization test offers the suggestions that keep inlet baffles completely open and regulate air fan loads only by hydraulic couplers. It earns about 20A of the primary air fan d_i,o, where input voltage is 6000V. The secondary air fan motor d_i,o changes from 2-27A depending on the fan load. A driver upgrading prediction shows that the primary air fan d_i,u would have been over 75A, and the primary air fan d_i,u would have been over 90A, if the hydraulic couplers are substituted for variable-frequency drive.

Abstract: Based on the aspects of thermal properties, resistance properties, air Leakage Control and boiler output adaptability, the operation modes and their impact of a quad-sector rotary airheater adopted by a 330MWe circulating fluidized bed boiler are analyzed by tests. And the operation methods of Leakage Control System are concluded. In order to improve the reliability of rotary airheater with main and auxiliary motors, recommendations for improvement are extended.

Abstract: A series of cryogenic methanol coil-wound heat exchangers with multi-stream and multiphase flows were researched and developed, including methanol-methanol cooler, cryogenic recycle methanol cooler, unshifted gas cooler, shifted gas cooler, feed gas cooler etc. The winding structure characteristics and the work principle of the spiral pipe bundles were elaborated to help the scientific design and calculation of coil-wound heat exchanger in cryogenic methanol field and to promote the research and development of standardization process. The major research directions and the critical scientific problems were forecasted.

Abstract: The research and development of LNG coil-wound heat exchanger (LCWHE) were discussed in view of the heat exchange in LNG field in petrochemical industry. The basic designing methods and the multi-stream heat exchange processes were illustrated by the cryogenic and high pressure crossing heat exchange equipments of LCWHE with multi-stream and multiphase flow, including Four-stream LCWHE in first stage, Three-stream LCWHE in second stage, Two-stream LCWHE in third stage, Multi-stream main LCWHE etc. A series of LCWHE with different mixed refrigerant and different applications were described. The winding structure characteristics and the working principle of the spiral pipe bundles were elaborated to give a reference for the scientific design and calculation of LCWHE in cryogenic field. The major researched directions and the critical scientific problems were forecasted.

Abstract: Using the finite-time thermodynamics, based on the thermodynamics properties of ferroelectric materials and a linear heat-transfer law, the inherent regenerative losses in the cycle are calculated and the fundamental optimum relations and other relevant performance parameters are determined. The thermoeconomic optimization for ferroelectric Ericsson refrigeration-cycle is reported. The cooling load for the refrigerator per unit total cost is proposed as objective functions for the optimization. The optimum performance parameters which maximize the objective functions are investigated. Since the optimization technique consists of both investment and energy consumption costs, the obtained results are more general and realistic.

Abstract: To predict accurately the fuel consumption rate of a diesel engine, based on polynomial fitting curve method, combined with the test data of XCW6200ZC medium speed marine diesel engine used for inland ships, a diesel engine fuel consumption model about characteristic coefficient and speed under the propulsion characteristic was established. The marine diesel engine fuel consumption were calculated and predicted through this model. The results showed that the model can predict the fuel consumption of diesel engine well.

Abstract: The characteristics of working medium is one of the important factors for organic Rankine cycle.The study is based on the waste heat of power plant,7 kinds working medium are selected,include R245fa, R600, R600a, R601a, R236fa, R236ea and RC318.ORC's thermodynamic cycle characteristics are calculated based on the first law of thermodynamics,then,compared the thermal efficiency,evaporating pressure and power ratio of different working medium.Results show that R245fa and R601a as the ORC system working medium have higher thermal efficiency and power ratio,and lower evaporating pressure than other five working medium,are ideal organic working medium to recycle flue gas waste heat of power plant.Secondly,R600 as system cycle working medium also has relatively good performance,can be the appropriate choice of working medium.

Abstract: This article considers two alternate solutions of a thermal balance equation. The first solution allows us to trace the decrease of a flammable liquid surface temperature to a temperature lower than fuel flash point at which combustion is stopped. And the second solution allows us to analyze the decrease of burnout rate to a negligible value at which steam-air mixture becomes nonflammable.

Abstract: Changing "high consumption energy, low temperature heat to the indoor, waste heat to the environment", and turning the HVAC harmoniously into the natural ecological cycle, conform to the trend of the development of ecological architecture. Heat pump technology is a way of HVAC energy saving the most practical. Although low heat and cold source of the city sewage is ideal, but the quality is very unstable, can not meet the operation requirements of heat exchange equipment. This paper analyzes the key problems of the sewage side in sewage source heat pump technology application in the present: hair dirt clog sewage heat exchanger; fouling in heat surface reduces the heat transfer performance, and results in large heat-transfer equipment in the practical application. According to the key problems of sewage side, this paper prevents hair clogged with large tube heat exchanger; reduces the fouling thermal resistance, and enhances heat transfer process using the heat exchanging technology of circulating fluidized bed.

Abstract: To improve the heat transfer performance of laminar tubular flow, a center-cleared twisted tape of alternate axes was developed as inserts. Numerical simulation was conducted to investigate the effect of dislocation angle of twisted tapes on the thermo-hydraulic performances. The numerical results show that, the largest Nusselt number occurs at a dislocation angle of 60°. The friction factor f is relatively larger than that when the dislocation angle is 0°, and it exhibits an obvious increment with the dislocation angle. From the value of performance evaluation criterion (PEC), the best thermo-hydraulic performance is achieved at a 60° dislocation angle. The underlying mechanisms are analyzed in terms of flow field and temperature field.