Thermal and Mechanical Characteristics of a Multifunctional Thermal Energy Storage Structure
Thermal energy storage (TES) sandwich-structures that combine the heat storage function with structural functionality are described. The structure consists of a thermal interface (TI) connected to a hollow plate lamination. Each laminate is a hollow aluminum plate having a series of mm-scale channels or compartments that are filled with phase change material (PCM). Heat storage is via the latent heat of the PCM. A generalized thermal response model that is applicable to a wide range of channel geometrical configurations is described. The model couples the thermal response of the TI to the hollow aluminum plate/PCM-volume. The temporal response of the system is easily obtained via numerical solution of two ordinary differential equations, which can be solved to give closed-form solutions subject to a simple assumption. Thermal analysis delineates geometrical configurations that have good thermal response characteristics. The mechanical properties of the laminated structure are determined experimentally. Four-point bending experiments are conducted using specimens made with three layers of hollow plates laminated using a structural adhesive. An energy method is developed to model both the deformation and strength of the laminated structure. The energy method is developed based on the assumption that plane cross sections of the structure remain plane under bending, a condition that is valid for both linear and nonlinear materials. The energy method can provide deformation of the aluminum laminates comparable with the experiments. Experiments and modeling indicate that these laminated structures have an excellent performance-to-weight ratio.
Numerical study of the spacecraft thermal control hardware combining solid–liquid phase change material and a heat pipe
Abstract A new spacecraft thermal control hardware composed of two parallel channels working for heat pipe (HP) and solid–liquid phase change material (PCM), respectively, is suggested for the high heat dissipating component which works intermittently with short duty. In present study the honeycomb structure radiator embedded with the device combining HP and PCM is designed, and the detailed thermal math models are developed for numerical analysis. The comparison of computational results between with and without PCM shows that the HP–PCM device redistributes temporal peak heat around a whole orbit period through alternate melting and freezing of PCM, and, as a result, the maximum and minimum temperatures are effectively alleviated. The drawback of PCM application due to low thermal conductivity can be successfully resolved by means of parallel arrangement of the HP channel. The suggested HP–PCM device can be a kind of off-the-shelf component and it does not require any case dedicated configuration. Therefore, it can be used with less impact on the program cost and schedule different from most of the PCM applications.
Comparison between Two Chemicals for Reducing Scale Formation in Reverse Osmosis Systems
In this present research was transacted with the calcium carbonate scale inhibition on the membrane surface of the reverse osmosis desalination system. Influence of changing feed solution flow rate (10-25)l/h, pH of the feed solution (6-10) on the recovery ,penetrate flow rate and total dissolved solid in (RO) system by using solution of calcium carbonate as feed solution was investigated, furthermore the effect of adding two types of scale inhibitor ,zinc chloride and polyamino polyether methylene phosphonate with difference concentration (2-8)mg/l for zinc chloride and (8-15) mg/l for polyamino polyether methylene phosphonate was calculated. The results showed that the permeate rate increases as the feed flow rate augmentation ,while it reducing with time, the total dissolved solids decreases as the feed flow rate increases while it increases with time and recovery rate decreases as the feed flow rate increases and it also decreases with time. It was concluded that the permeate rate decreases as the feed solution pH value increases and it cause high scale forming thus decrease the permeate TDS.By adding the scale inhibitor, it was found that the permeate rate and recovery rates increases as the concentration of inhibitor increases while the total dissolved solids decreases in the permeate with increasing the concentration of both inhibitors .It was discovered that Polyamino polyether methylene phosphonate more sturdy than zinc chloride as scale inhibitor for reverse osmosis desalination system in all concentrations was studied in this article.