intend of giving Sadaka.Which is better sending a poor muslim broter to Hadj or feed hungry muslin children.If feeding hungry Children is more important what if i have already make niyat to send some one to hadj this year if i can afford it

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.

Giving charity to the poor and destitute who need food, drink, dwelling and medicines is more important and better and greater in reward than paying the expenses for someone to go for Hajj. That is because by feeding hungry people, you are benefiting many people, saving their lives and fulfilling their needs. However, shouldering the expenses of Hajj benefits only the person who performs Hajj. If such a person is unable [he does not have the financial means and is unable physically] to perform Hajj, he is excused, and if he is able, then he is obliged to perform Hajj from his own money.

Therefore, if you can combine the two things, then this is better, as you will donate to the poor and destitute and help someone to perform Hajj, but if this is not possible, then feeding the hungry comes in priority, and you are not sinful for intending to pay the expenses for someone to perform Hajj and ultimately you fail to do so. 

We ask Allaah to reward you and increase your zeal in benefiting the Muslims.