Browsing by Author "Kimambo, Cuthbert Z."

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    Analytical Evaluation of Head and Flow Rate Off-Design Characteristics for Pump as Turbine Application
    (The American Society of Mechanical Engineers, 2019) Mdee, Ombeni J.; Kimambo, Cuthbert Z.; Nielsen, Torbjorn K.; Kihedu, Joseph
    Head and flow rate are the important parameters for proper selection of centrifugal pump. However, the reversed operation of centrifugal pump leads to the off-design characteristic of head and flow rate. This paper presents an analytical model developed by using the system curves and velocity relations derived from pump application. Also, the differential technique is applied to the analytical model to develop the off-design characteristics of head ratio and flow rate ratio relations. The off-design characteristic relations were compared with literature and available conversion methods. Then, the analytical model coefficient (AMC) with the range between −4 and +4 was developed from the off-design characteristics of head ratio and flow rate ratio relations. The AMC value was equal to 1 when the pump operates in turbine mode and pump mode at the pump best efficiency point (BEP) and extended to either side up to ±4 when tested with literature data. Therefore, the analytical model consists of the off-design head and flow rate characteristics, when simplified leading to the AMC that could be applied to select the possible boundary limits of head and flow rate for different pumps.
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    Assessment of hydropower resources in Tanzania. A review article
    (EDP Sciences, 2018) Mdee, Ombeni J.; Nielsen, Torbjorn K.; Kimambo, Cuthbert Z.; Kihedu, Joseph
    The hydropower resources have become an attractive means of generating electricity to the off-grid network, especially in rural areas. This article assesses the small, mini and large hydropower resources and identified to reach 5.3GW for electricity generation in Tanzania. The technology development discussed comprises of hydro turbine manufacturers, classification and turbine selection. The barriers presented include the presence of sediment in the hydropower reservoirs, financial viability, policy and regulatory issues related to hydropower development. This reviewed article serves the investors and policymakers to understand the status of hydropower resources in Tanzania.
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    Measurement methods for hydropower resources: a review
    (E.W. Publications, 2018) Mdee, Ombeni J.; Kimambo, Cuthbert Z.; Nielsen, Torbjorn K.; Kihedu, Joseph
    Each hydropower plant is usually designed for specific amount of discharge and gross head. This paper presents the methods used to measure the discharge and gross head variables with additional of assessment tools. Discharge measurement methods covered include bucket, float, velocity-area, dilution, hydraulic structure and advanced discharge measurement while gross head measurement methods covered include topographic and DEM maps, hose level with pressure gauge, sight level, spirit level and advanced survey instruments. The assessment tools presented include SMART MINI-IDRO, Integrated Method for Power Analysis, VIPIDRO ASTE 4.0, Hydromatch, Hydrohelp and Renewable Energy Technology Screen tool. The assessment tools used to estimate the potential of hydropower resources in terms of energy, hydropower plant components and financial analysis. Therefore, this review paper indicated the possibility of conducting a pre-feasibility study of hydropower estimation by using the open access tools and accessible equipment in the carpentry and mason works, especially in the developing countries.