Optimization of a solar air heater with phase change materials: Experimental and ‎numerical study

In this paper, a solar air heater (SAH) with phase change material (PCM)-based energy storage is ‎investigated. Paraffin was placed underneath the absorber plate as the PCM. A transient two-‎dimensional laminar model was used in the Ansys Fluent 17 software to study the effects of different ‎parameters on the performance of the SAH, such as the air mass flow rate, the amount of paraffin, and ‎the thermal conductivity of the paraffin. The performance of the SAH was optimized by considering ‎two objectives simultaneously: thermal energy efficiency and maximum nocturnal temperature ‎difference between the inlet and the outlet of the SAH. To validate the numerical model, a SAH with ‎a 2-cm paraffin layer and the same dimensions as the numerical model was built and tested. The ‎results of the simulation showed good agreement with the experimental results.

Presentation of DNA Methyltransferase 3 Beta Mutation with Immune Deficiency and Dilation of Aorta and Esophagus

Background: Immunodeficiency, Centromeric region instability, and Facial anomalies syndrome (ICF) is a rare autosomal recessive disorder with Centromeric instability as a hallmark. Method: In this case report, we describe an Iranian 6-year-old male who was diagnosed with ICF syndrome. He had a history of recurrent infections, hydrocephalus report in pregnancy, failure to thrive, facial anomalies, global developmental delay, and umbilical hernia. Results: The investigation showed esophageal dilatation in barium swallow, ascending aortic dilatation in echocardiography and cutis laxa in skin biopsy. In laboratory data, impaired antibody function was observed. Finally, to find the probable causative genetic variant, a whole exome sequencing was performed. The data analysis using bioinformatics tools revealed c.1592G>A mutation in the exon 15 of DNMT3B. With respect to the diagnosis of ICF syndrome, our patient was treated with intravenous immunoglobulin (IVIG). Conclusion: It is necessary to perform periodic neurologic and ophthalmologic examinations. Echocardiography must be done annually. In addition, the possibility of HSCT should be evaluate

Application of Permutation Genetic Algorithm for Sequential Model Building–Model Validation Design of Experiments

YesThe work presented in this paper is motivated by a complex multivariate engineering problem associated with engine mapping experiments, which require efficient Design of Experiment (DoE) strategies to minimise expensive testing. The paper describes the development and evaluation of a Permutation Genetic Algorithm (PermGA) to support an exploration-based sequential DoE strategy for complex real-life engineering problems. A known PermGA was implemented to generate uniform OLH DoEs, and substantially extended to support generation of Model Building–Model Validation (MB-MV) sequences, by generating optimal infill sets of test points as OLH DoEs, that preserve good space filling and projection properties for the merged MB + MV test plan. The algorithm was further extended to address issues with non-orthogonal design spaces, which is a common problem in engineering applications. The effectiveness of the PermGA algorithm for the MB-MV OLH DoE sequence was evaluated through a theoretical benchmark problem based on the Six-Hump-Camel-Back (SHCB) function, as well as the Gasoline Direct Injection (GDI) engine steady state engine mapping problem that motivated this research. The case studies show that the algorithm is effective at delivering quasi-orthogonal space-filling DoEs with good properties even after several MB-MV iterations, while the improvement in model adequacy and accuracy can be monitored by the engineering analyst. The practical importance of this work, demonstrated through the engine case study, also is that significant reduction in the effort and cost of testing can be achieved.The research work presented in this paper was funded by the UK Technology Strategy Board (TSB) through the Carbon Reduction through Engine Optimization (CREO) project

Numerical Analysis of Thermal Conductivity of Non-Charring Material Ablation Carbon-Carbon and Graphite with Considering Chemical Reaction Effects, Mass Transfer and Surface Heat Transfer

Nowadays, there is little information, concerning the heat shield systems, and this information is not completely reliable to use in so many cases. for example, the precise calculation cannot be done for various materials. In addition, the real scale test has two disadvantages: high cost and low flexibility, and for each case we must perform a new test. Hence, using numerical modeling program that calculates the surface recession rate and interior temperature distribution is necessary. Also, numerical solution of governing equation for non-charring material ablation is presented in order to anticipate the recession rate and the heat response of non-charring heat shields. the governing equation is nonlinear and the Newton- Rafson method along with TDMA algorithm is used to solve this nonlinear equation system. Using Newton- Rafson method for solving the governing equation is one of the advantages of the solving method because this method is simple and it can be easily generalized to more difficult problems. The obtained results compared with reliable sources in order to examine the accuracy of compiling code

Axisymmetric stagnation-point flow and heat transfer of a viscous, compressible fluid on a cylinder with constant heat flux

AbstractExisting solutions of the problem of axisymmetric stagnation-point flow and heat transfer on either a cylinder or flat plate are for incompressible fluid. Here, fluid with temperature dependent density is considered in the problem of axisymmetric stagnation-point flow and heat transfer on a cylinder with constant heat flux. The impinging free stream is steady and with a constant strain rate, k̄. An exact solution of the Navier–Stokes equations and energy equation is derived in this problem. A reduction of these equations is obtained by use of appropriate transformations introduced for the first time. The general self-similar solution is obtained when the wall heat flux of the cylinder is constant. All the solutions above are presented for Reynolds numbers, Re=k̄a2/2υ, ranging from 0.01 to 1000, selected values of compressibility factors, and different values of Prandtl number, where a is cylinder radius and ν is the kinematic viscosity of the fluid. For all Reynolds numbers and surface heat flux, as the compressibility factor increases, both components of the velocity field, the heat transfer coefficient and the shear-stresses increase, and the pressure function decreases

Numerical Analysis of Thermal Conductivity of Non-Charring Material Ablation Carbon-Carbon and Graphite with Considering Chemical Reaction Effects, Mass Transfer and Surface Heat Transfer

Nowadays, there is little information, concerning the heat shield systems, and this information is not completely reliable to use in so many cases. for example, the precise calculation cannot be done for various materials. In addition, the real scale test has two disadvantages: high cost and low flexibility, and for each case we must perform a new test. Hence, using numerical modeling program that calculates the surface recession rate and interior temperature distribution is necessary. Also, numerical solution of governing equation for non-charring material ablation is presented in order to anticipate the recession rate and the heat response of non-charring heat shields. the governing equation is nonlinear and the Newton- Rafson method along with TDMA algorithm is used to solve this nonlinear equation system. Using Newton- Rafson method for solving the governing equation is one of the advantages of the solving method because this method is simple and it can be easily generalized to more difficult problems. The obtained results compared with reliable sources in order to examine the accuracy of compiling code

Numerical combustion modelling of a gas-burner

In this paper numerical simulation of combustion over a sample of a prevalent gas-burner, and effects of parameters such as environment geometry, main parameters of chimney, effect of free and forced convection on the environment, in radiation modelling situation and without radiation has been studied. Since offering proposals to improve the efficiency of a system is required for completing identification of the system, gas-burner is set in different cases in the environment to have better recognition of the manner of gas-burner heat transfer to the environment. For study of radiation effects, a geometric model considering radiative heat transfer and without radiation is simulated and the results compared together. Furthermore, the distribution of environmental temperature in normal conditions, and advert to mass fraction of combustion products are the other cases which have been studie